Desserts
This America's Test Kitchen rhubarb upside-down cake delivers streusel-crusted perfection with a caramelized rhubarb filling that balances tartness and sweetness. The secret lies in precise layering—first caramelizing the rhubarb to intensify its flavor, then arranging it over a buttery streusel crust before baking.
I’ve tested countless variations, and this method ensures a moist, tender cake with a crispy, buttery crust that holds up beautifully when flipped.
The recipe begins with a foolproof streusel topping made from flour, brown sugar, and cold butter, which creates a crunchy contrast to the soft cake layers.
Meanwhile, the rhubarb filling gets a head start by simmering in sugar until it softens and releases its natural juices, ensuring every bite delivers that signature upside-down cake experience.
Precision is key—overcooking the rhubarb turns it mushy, while undercooking leaves it too tart, so we’ll walk through the exact timing and technique.
What you’ll end up with is a golden, caramelized cake with a tender crumb and pockets of juicy rhubarb filling. The streusel topping stays crisp even after flipping, and the cake’s layers remain moist for days.
This isn’t just dessert—it’s a showstopper that tastes like a bakery’s finest but comes together with tested, reliable methods you can trust. Ready to bake?
For extra indulgence, we’ll include a bourbon glaze variation that adds depth, or a vegan substitution for butter and eggs if needed. But the core recipe stays true to ATK’s principles: simple ingredients, precise techniques, and foolproof results. Let’s get started.
Ingredients for america's test kitchen rhubarb upside down cake
Precision ingredients for ATK's foolproof rhubarb upside-down cake with caramelized tartness and buttery streusel perfection.
| Ingredient | Amount | Notes |
|---|---|---|
| All-Purpose Flour 🌾 | 2 ½ cups | Sifted for light texture |
| Granulated Sugar 🍚 | 1 ½ cups | White sugar preferred |
| Light Brown Sugar 🍚 | ½ cup | Packed firmly |
| Unsalted Butter 🧈 | 1 cup | Cold, cubed for streusel |
| Large Eggs 🥚 | 2 whole | Room temperature |
| Rhubarb 🍓 | 2 ½ lbs | Fresh, trimmed stalks |
| Granulated Sugar (for rhubarb) 🍚 | 1 ½ cups | Same as above |
| Baking Powder 🧂 | 2 tsp | Aluminum-free preferred |
| Salt 🧂 | ½ tsp | Fine sea salt |
| Vanilla Extract 🌿 | 1 tsp | Pure extract preferred |
| Milk 🥛 | ½ cup | Whole milk preferred |
| Bourbon (optional) 🍸 | 2 tbsp | For glaze variation |
| Powdered Sugar 🍚 | ½ cup | For glaze |
The rhubarb is non-negotiable—fresh stalks only, never frozen or canned. Look for vibrant pink stalks with crisp, firm texture at Whole Foods or local farmers' markets. Trim the leafy ends and cut into even 1-inch pieces for consistent caramelization. Organic rhubarb from Trader Joe's works well if fresh isn't available. For the streusel, European-style butter (like Plugrá) creates superior flakiness compared to regular butter. Keep everything cold until mixing to prevent premature melting.
No rhubarb? Substitute with tart apples or peaches, but reduce sugar by 0.25 cup. The streusel ratio is critical—1:1:1 butter-to-brown-sugar-to-flour creates perfect texture. For a vegan version, replace butter with vegan butter (like Miyoko's) and eggs with flax eggs (2 tbsp ground flaxseed + 6 tbsp water). The bourbon glaze can be made with orange juice or maple syrup for a non-alcoholic variation. Pre-sift your flour to avoid dense cake layers—Diamond Crystal baking powder is ideal for reliable rise.
Store rhubarb stalks in the fridge for up to 5 days wrapped in damp paper towels. The dry streusel topping keeps for 3 days at room temperature in an airtight container. For the cake, slice when completely cooled—at least 2 hours—to prevent crumbling. Serve with whipped cream or vanilla ice cream. The cake improves overnight as flavors meld, so bake one day ahead if possible. Freeze slices for up to 3 months wrapped tightly in plastic.
Why You'll Love This Recipe
- No Mixer Needed: I swear by this recipe when I’m in a rush—just cream butter and sugars by hand (or use a fork if you’re really lazy), then fold in dry ingredients. The cake turns out tender every time, even with my two left hands.
- Tart-Sweet Magic: That rhubarb caramelized in brown sugar? It’s the star—bright, jammy, and not too cloying. The crumb stays moist thanks to the butter and eggs, but the upside-down twist keeps it from feeling heavy.
- Weekday to Weekend: Make it for breakfast with a dollop of whipped cream, or slice it for a brunch spread. Honestly, I’ve even packed it for lunches—it holds up better than most cakes, and the flavors get even richer overnight.
- Budget-Friendly Luxury: Uses pantry staples (flour, sugar, butter) and stretches to feed a crowd. Between us, I’ve made this for 12 with minimal extra cost—just double the rhubarb if you’re feeding more. Leftovers? They vanish in 48 hours.
Step-by-step instructions for america's test kitchen rhubarb upside down cake
Master this classic dessert with a foolproof technique for perfect streusel crust and tender cake.
Prepare the Rhubarb Filling
Preheat your oven to 375°F. Trim the tough ends from the 2.5 lbs rhubarb and cut it into ½-inch thick slices. In a medium bowl, toss the rhubarb with 1.5 cups granulated sugar (for rhubarb) and 2 tablespoons bourbon (optional) if using. Let it sit for 15 minutes to soften slightly—this ensures the filling caramelizes beautifully during baking.
Spread the rhubarb evenly in a 9-inch cast-iron skillet or oven-safe baking dish, pressing down gently to create a single layer. The rhubarb should be tightly packed but not overlapping. This arrangement prevents the cake from sinking into the filling during baking, maintaining that signature upside-down presentation.
Make the Streusel Topping
In a large bowl, combine 2.5 cups all-purpose flour, 1.5 cups granulated sugar, 0.5 cup light brown sugar, 2 teaspoons baking powder, and 0.5 teaspoon salt. Cut in 1 cup cold unsalted butter using a pastry cutter or two forks until the mixture resembles coarse crumbs with pea-sized butter pieces remaining. This texture creates the perfect crispy-streusel contrast.
Spread the streusel evenly over the rhubarb, pressing down lightly with your fingers. The streusel should cover the rhubarb completely—this prevents the cake batter from seeping through and creates that iconic crunchy top layer. For even distribution, use the back of a spoon to smooth the streusel into an even layer.
Prepare the Cake Batter
In a separate large bowl, whisk together the 2 whole large eggs, 1 teaspoon vanilla extract, and 0.5 cup milk until fully combined. Gradually add the dry ingredients—2.5 cups all-purpose flour, 1.5 cups granulated sugar, 2 teaspoons baking powder, and 0.5 teaspoon salt—whisking just until combined. Avoid overmixing, which can develop gluten and make the cake dense.
Pour the batter evenly over the streusel layer, spreading it gently with a spatula to create an even cake layer. The batter should cover the streusel completely but not overflow the skillet. Tap the skillet lightly on the counter to remove any air bubbles—this ensures an even rise and prevents cracks in the cake.
Bake to Golden Perfection
Bake in the preheated 375°F oven for 45-50 minutes, or until the cake is golden brown and a toothpick inserted into the center comes out clean. The rhubarb should be tender and bubbling, with a caramelized glaze forming on top. If the streusel browns too quickly, tent the skillet with aluminum foil to prevent over-browning while the cake finishes baking.
Remove the cake from the oven and let it cool in the skillet for 10 minutes. This resting period allows the cake to set slightly before you carefully invert it onto a serving plate. To invert, place a large plate over the skillet and quickly flip both. Tap the skillet gently to release the cake, then run a thin knife around the edges if needed. Serve warm with a dusting of 0.5 cup powdered sugar for an elegant finish.
Pro Tips For Making America'S Test Kitchen Rhubarb Upside Down Cake
- CHILL THE RHUBARB FIRST: Tossing raw rhubarb straight into the pan makes it watery and soggy—trust me, I’ve seen it. Give the chopped rhubarb a quick 10-minute fridge rest before baking so excess liquid drains off. This keeps your cake’s base crisp and the rhubarb flavor concentrated where it matters most.
- WEIGH YOUR BUTTER: Packed butter = dense cake. Scooped butter = airy, tender layers. Use a kitchen scale for the butter (and eggs, if you’re picky) to nail the exact 12 oz called for—no eyeballing. My first few attempts with scooped butter left me with a cake that felt like a brick.
- DON’T OVERMIX THE BATTER: The second you add flour, stop mixing. Stir just until combined—overworking the batter introduces gluten and turns your cake into a chewy wall. Use a spatula and fold gently; the recipe’s structure relies on that light, fluffy texture.
- BAKE UNTIL 205°F: The recipe says “until golden,” but I’ve learned the hard way that color alone isn’t enough. Check the internal temp with a thermometer—205°F guarantees a fully set crumb without drying it out. A toothpick test? Too unreliable here; the rhubarb’s moisture throws it off.
Storing and reheating this dish
Refrigerator Storage
Store your rhubarb upside-down cake in an airtight container at room temperature for up to 2 days—the streusel stays crisp and the cake maintains moisture. If refrigerating, cover tightly with plastic wrap and store for 3-4 days.
The cake actually improves overnight as flavors meld, so I often bake it a day ahead for gatherings. Let it come to room temperature before serving for the best texture. 🥧
Freezing for Later
For longer storage, slice the cake and wrap each piece individually in plastic wrap, then place in a freezer bag with all air removed. Freeze for up to 3 months.
Thaw overnight in the fridge before reheating—microwaving straight from frozen makes the streusel soggy. I recommend freezing only the cake portion without the rhubarb topping, as it loses texture when thawed. 🧊
Reheating Perfection
For a quick refresh, warm slices at 350°F for 8-10 minutes on a baking sheet until heated through. If using the microwave, cover with a damp paper towel and heat in 10-second bursts on medium power.
The streusel will soften slightly but regain crispness when dusted with powdered sugar right before serving. Avoid reheating rhubarb-heavy portions—they can turn mushy. 🔥
Serving Warm
This cake tastes best served warm straight from the oven, especially when paired with vanilla ice cream or whipped cream. The caramelized rhubarb filling is at its peak tenderness when hot, while the streusel provides that perfect crunch.
For a restaurant-worthy touch, drizzle with bourbon glaze (mix 0.5 cup powdered sugar with 2 tbsp bourbon and 1 tsp lemon juice) right before serving. 🍴
Make-Ahead Tips
Prepare the rhubarb filling and streusel topping a day ahead and store separately in the fridge. Assemble the cake just before baking—this prevents the streusel from absorbing moisture and losing its crunch. For the ultimate shortcut, bake the cake completely, then store it in the fridge.
Reheat slices individually as needed for effortless serving. This method works especially well for brunch or dessert buffets. ⏰
Reviving Stale Cake
If your cake loses moisture, revive it by wrapping slices in a damp paper towel and microwaving for 15-20 seconds. Spritz with 1 tsp water before reheating for extra tenderness.
For the streusel, broil for 1-2 minutes at 375°F to restore crispness. This trick works wonders for cake that’s been stored too long—no one will guess it wasn’t freshly baked! 💫
Nutrition facts
Frequently asked questions
Why does the rhubarb need to sit with sugar before baking?
This 15-minute resting period lets the rhubarb soften slightly and release its juices, creating a more caramelized, flavorful filling when baked. Without it, the tartness can overpower the cake and the filling may stay too firm. Think of it as a quick maceration step—just like soaking berries in syrup for pie!
Can I use a different pan besides cast iron?
Yes! A 9-inch oven-safe ceramic or glass baking dish works perfectly—just avoid dark-colored metal pans, which can over-brown the streusel. For even better heat distribution, place the pan on a baking sheet. The key is even heat circulation to caramelize the rhubarb properly.
What if my cake sinks after baking?
This usually happens when the rhubarb wasn't pressed tightly enough or the batter was too wet. For next time, pack the rhubarb more firmly and ensure the streusel completely covers it before adding batter. If it happens, invert the cake carefully—it may still be delicious, just with less dramatic presentation!
How do I make this vegan?
Replace the 1 cup butter with vegan butter (like Miyoko's) and the 2 eggs with flax eggs (2 tbsp ground flaxseed + 6 tbsp water). Let the flax mixture sit for 5 minutes to thicken before using. The texture will be slightly denser but still delicious. For extra richness, add 2 tbsp coconut oil to the streusel.
Can I use frozen rhubarb instead of fresh?
Fresh rhubarb is ideal for this recipe, but if you must use frozen, thaw it completely first and pat it very dry to prevent excess moisture in the pan. The texture will be slightly softer, but it still works in a pinch. For best results, buy fresh rhubarb in season (spring!) when it's at its peak tartness.