For the cake:
- 8 tbsp. (113 grams) unsalted butter, at room temperature
- 1¼ cups (250 grams) granulated sugar
- 3 tbsp. (50 grams) light brown sugar
- 3 large eggs
- ½ cup (110 grams) buttermilk
- 1/3 cup (65 grams) grapeseed oil
- ½ tsp. (2 grams) vanilla extract
- ½ tsp. (2 grams) almond extract
- 2 cups (245 grams) cake flour
- 1½ tsp. (6 grams) baking powder
- ¾ tsp. (3 grams) kosher salt
For the berry crumb:
- ¼ cup (20 grams) milk powder
- 2 tbsp. (20 grams) all-purpose flour
- 1 tbsp. (6 grams) cornstarch
- 1 tbsp. (13 grams) granulated sugar
- ¼ tsp. (1 gram) kosher salt
- 2 tbsp. (28 grams) butter, melted
- ¼ cup (15 grams) freeze-dried strawberries
- ¼ cup (15 grams) freeze-dried raspberries
- 1½ oz. (45 grams) white chocolate, melted
For the blackberry curd:
- ½ cup (100 grams) blackberry puree*
- 1/3 cup (65 grams) granulated sugar
- 2 large eggs
- 2 tsp. water
- ½ tsp. powdered gelatin
- 12 tbsp. (170 grams) butter, very cold
- ½ tsp. (2 grams) kosher salt
For the blackberry sauce:
- 3 cups (330 grams) fresh blackberries
- 6 tbsp. (78 grams) sugar
- 1 tbsp. (6 grams) cornstarch
- 1 tbsp. (15 grams) water
- 1 tbsp. (15 grams) freshly squeezed lemon juice
For the soak:
- ¼ cup (60 grams) milk
For the frosting:*
- 4 tbsp. (56 grams) butter
- ½ cup (63 grams) confectioners’ sugar
- Pinch of salt
- 2 tsp. (10 grams) heavy cream
- 1-2 tbsp. (15-30 grams) blackberry puree
step 1: Show Images
To make the cake, heat the oven to 350˚ F. Butter and flour the edges of a quarter sheet pan. Line the bottom of the pan with parchment paper. In the bowl of an electric mixer, combine the butter and sugars. Beat on medium-high speed for 2-3 minutes, until fluffy. Scrape down the sides of the bowl, add in the eggs, and mix on medium-high for 2-3 minutes more. Scrape down the sides of the bowl again.
step 2: Show Images
With the mixer on low speed, stream in the buttermilk, oil, vanilla and almond extracts. Increase the speed to medium-high and mix for 4-6 minutes, until the mixture is nearly white and twice the size of the original batter, and completely homogenous (there should be no streaks of fat or liquid.) Scrape down the sides of the bowl. With the mixer on very low speed, add in the cake flour, baking powder, and salt. Mix for 45-60 seconds, just until the batter comes together. Spread the batter in the prepared quarter sheet pan.
step 3: Show Images
Bake for 30-35 minutes, rotating the pan once halfway through baking, until the cake is puffed and the center is no longer jiggly (the cake should bounce back when lightly poked with your finger.) Transfer to a wire cooling rack and let cool completely.
step 4: Show Images
To make the berry crumb, heat the oven to 250˚ F. Line a baking sheet with a silicone baking mat. In a bowl, combine the milk, powder, flour, cornstarch, sugar and salt. Add in the melted butter and toss with a fork until the mixture clumps together and forms small clusters. Spread the clusters out on the baking sheet and bake for 20 minutes. Remove from the oven and let cool completely.
step 5: Show Images
Once the crumbs are cooled, transfer them to a large plastic bag. Place the freeze-dried berries in a food processor and pulverize until they are a fine powder. Drizzle the melted white chocolate over the crumbs in the plastic bag. Add in the berry powder, close the bag, and shake well to mix together with the crumbs. Let cool until the chocolate is set.
step 6: Show Images
To make the blackberry curd, put the blackberry puree in a blender with the sugar and blend until the sugar granules have dissolved. Add the eggs and blend on low until the mixture is smooth. Transfer the contents of the blender to a medium pot or saucepan, and clean out the blender canister. Place the water in a small bowl and sprinkle the gelatin evenly over the top to bloom the gelatin. In the saucepan, heat the blackberry mixture over low heat, whisking often. It will begin to thicken as it heats up. Once it boils, remove it from the heat and transfer to the clean blender canister. Add in the bloomed gelatin, butter, and salt, and blend until the mixture is thick, shiny and very smooth. Transfer to a heatproof container, cover and refrigerate until completely cool, at least 1 hour.
step 7: Show Images
Combine the blackberries and sugar in a nonreactive saucepan over medium-high heat. Cook, stirring occasionally, until the berries begin to release their juices. In a small bowl combine the cornstarch with the water and lemon juice and whisk until smooth. Stir the cornstarch mixture into the blackberry mixture. Bring to a boil, then reduce the heat to a simmer and cook for 1 minute more. Remove from the heat. Puree using a blender or immersion blender. Strain through a fine mesh sieve to remove the seeds. Transfer to a storage container, cover and chill.
step 8: Show Images
When you are ready to assemble the cake, prepare the frosting. Place the butter in the bowl of an electric mixer. Whip on medium-high speed until smooth, about 1 minute. Add the confectioners’ sugar to the bowl and mix on medium-low speed just until incorporated. Add in the salt and heavy cream and mix on low speed just until incorporated. Increase the mixer speed and whip on high speed until light and fluffy, scraping down the bowl as needed, about 3-4 minutes. Blend in 1 tablespoon of the blackberry puree to start with. Check flavor, texture, and color, and add more if necessary.
step 9: Show Images
To assemble the cake, invert the cake from the sheet pan onto a work surface. Use a 6-inch cake ring to cut out 2 circles from the cake (these will be the top two layers.) Wipe off the cake ring and place it in the center of a sheet pan lined with clean parchment or a silpat. Use a strip of acetate to line the inside of the cake ring. Use scraps from the leftover cake to place in the ring and tamp together in a flat, even layer. Use a pastry brush to soak the top of this cake layer with about half of the milk. Spread about half of the berry curd over the cake. Sprinkle with an even layer of the berry milk crumb (about one third), pressing down with the back of your hand to adhere the crumbs to the curd. Carefully spread about half of the blackberry sauce over the crumbs. Gently tuck a second strip of acetate between the cake ring and the top ¼-inch of the first strip of acetate. Set a cake round on top of the blackberry sauce, and repeat the layering process once more (milk soak, blackberry curd, berry milk crumb, blackberry sauce.) Place the remaining cake layer onto top of the blackberry sauce. Top with a thin layer of the frosting. Sprinkle additional berry milk crumb over the top for garnish.
step 10: Show Images
- You will make the blackberry puree by simply pureeing fresh or thawed frozen blackberries in a blender or food processor and straining out the seeds. Make a little bit more than is needed for the curd so you will have some to blend into the frosting.
- Frosting can be difficult to make in small quantities due to mechanics of electric mixers. You may want to make a double batch for easier mixing.