Equipment
Ingredients
Caramelized Berry Layer
- 60 g unsalted butter, chilled or room temperature
- 120 g dark brown sugar, packed
- 15 ml fresh lemon juice, strained
- 1 g fine sea salt
- 300 g mixed berries
Lemon Buttermilk Sponge
- 190 g all-purpose flour
- 6 g baking powder
- 2 g baking soda
- 3 g fine sea salt
- 150 g granulated sugar
- 5 g lemon zest, freshly grated
- 85 g unsalted butter, softened to room temperature
- 2 egg, room temperature
- 5 ml pure vanilla extract
- 120 ml buttermilk, room temperature
Nutrition (per serving)
Nutrition is estimated per serving. Nutrients without complete source data are omitted.
Full nutrition
- Calories
- 409 kcal
- Protein
- 5 g
- Carbohydrates
- 61 g
- Fat
- 16 g
- Fiber
- 1 g
- Sugar
- 40 g
- Sodium
- 391 mg
- Saturated Fat
- 10 g
- Potassium
- 183 mg
- Calcium
- 101 mg
- Iron
- 1.5 mg
- Magnesium
- 18 mg
- Phosphorus
- 93 mg
- Zinc
- 0.5 mg
- Vitamin A
- 147 mcg
- Vitamin C
- 9 mg
- Water
- 61 g
Sources: Aggregated Public Data, USDA FoodData Central
Method
Preheat the oven to 175°C (350°F) with an oven rack positioned in the center. Grease the sides and bottom of a 23cm round cake pan and line the base with a fitted circle of parchment paper.
Combine 60g unsalted butter, 120g dark brown sugar, 15ml fresh lemon juice, and 1g fine sea salt in a small saucepan over medium heat, stirring continuously until the butter melts and the mixture turns into a glossy, bubbling caramel.
Pour the molten brown sugar caramel directly into the parchment-lined cake pan, gently tilting the pan to cover the bottom in a smooth, continuous layer.
Scatter 300g mixed berries evenly across the warm caramel in a single, tight layer, setting larger fruit cut-side down if halved.
In a medium mixing bowl, whisk together 190g all-purpose flour, 6g baking powder, 2g baking soda, and 3g fine sea salt until aerated and uniform.
Place 150g granulated sugar and 5g fresh lemon zest into a large mixing bowl, and rub them together vigorously between your fingertips until the sugar turns pale yellow and releases a strong citrus fragrance.
Add 85g softened unsalted butter to the lemon sugar and beat with a whisk or electric hand mixer on medium speed until the mixture becomes pale, light, and airy.
Beat in the 2 room-temperature eggs one at a time, incorporating each fully before adding the next, then stir in 5ml vanilla extract until the emulsion is silky.
Gently fold the dry flour mixture and 120ml buttermilk into the creamed batter in three alternating additions using a rubber spatula, beginning and ending with dry ingredients, stopping as soon as flour streaks disappear.
Dollop the batter gently over the arranged berries and use a rubber spatula to smooth it into an even layer, taking care not to drag or disrupt the fruit beneath.
Bake the cake at 175°C (350°F) for 40 to 45 minutes until the cake top is deep golden brown and a wooden skewer inserted into the center of the crumb comes out clean, reaching an internal sponge temperature of at least 95°C (203°F).
Set the hot cake pan on a wire cooling rack and let it rest undisturbed for exactly 15 minutes to allow the bubbling fruit caramel to stabilize.
Run a thin offset spatula around the inside perimeter of the pan to release the sponge sides, invert a wide serving platter securely over the top, and invert both platter and pan together in one smooth motion.
Let the inverted pan rest over the cake for 2 minutes so all remaining caramel drips over the berries, then gently lift the pan off and peel away the parchment paper.
Chef's Notes
- A blend of tart raspberries, firm blackberries, and sweet blueberries creates the ideal balance of pectin, moisture, and contrasting colors across the top.
- Rubbing the lemon zest directly into the sugar ruptures the citrus oil glands and extracts maximum aromatics, cutting through the heavy brown sugar toffee.
- Do not use a springform pan for upside-down cakes; the molten butter-sugar caramel will seep past the base clasp and cause burning in the oven.
- Room temperature eggs and buttermilk are vital to prevent the creamed butter from curdling, which preserves an even, tender crumb.
Storage
Refrigerator: 4 days — Store in an airtight container once fully cooled to maintain crumb structure and keep the jammy fruit topping fresh.
Freezer: 1 month — Wrap individual sliced portions tightly in parchment paper and transfer to a sealed freezer container. Defrost overnight in the refrigerator.
Reheating: Warm individual slices on a baking sheet at 150°C (300°F) for 8 to 10 minutes until heated through, or microwave for 15 to 20 seconds.
Troubleshooting
Fruit and caramel stick stubbornly to the base of the pan after inversion
Cause: The cake was either inverted too late after the caramel hardened, or too early while it was still entirely liquid, or parchment paper was omitted.
Fix: Warm the underside of the inverted pan with a kitchen towel dampened in hot water for 30 seconds, then scrape any clinging berries from the pan and arrange them across the cake top.
Prevention: Always line the pan base with parchment paper and invert strictly within 12 to 15 minutes after removing from the oven.
The center of the cake beneath the fruit layer is gummy and dense
Cause: Excess water was present on washed berries, or the cake was underbaked in the middle.
Fix: Cannot be fixed once unmolded; ensure future bakes reach full interior temperature before inverting.
Prevention: Thoroughly dry fresh berries on paper towels before arranging, and verify doneness with a skewer reaching 95°C (203°F) before unmolding.
Caramel leaks out of the pan during baking and burns on the oven floor
Cause: A springform pan or loose-bottom cake tin was used instead of a solid-bottom pan.
Fix: Slide a foil-lined baking sheet on the rack below immediately to catch further drips and prevent acrid smoke.
Prevention: Always use a solid one-piece cake pan or cast-iron skillet, or place a rimmed baking sheet directly on the lower rack beneath the pan.
Cultural Context
Upside-down cakes became a staple of American home baking during the 1920s following marketing campaigns that paired cast-iron skillets with canned Hawaiian pineapple rings. By substituting seasonal summer bramble berries for tropical pineapple and caramelizing brown sugar with fresh lemon zest, this variation honors mid-century fruit buckle traditions while delivering a brighter, modern jam-like finish.
