⅔ cup unsalted butter at room temperature
1⅓ cups sugar
4 large eggs at room temperature
2 tsp vanilla extract
2¼ cups all-purpose flour
2 tsp baking powder
½ tsp salt
1¼ cups 2% milk at room temperature
8 ounces white chocolate, chopped
White Chocolate Buttercream & Assembly:
2 cups unsalted butter at room temperature
16 ounces good quality white chocolate, melted and cooled to room temperature
2 cups cing sugar, sifted
2 tsp vanilla extract
¼ tsp salt
3 cups fresh blackberries
1. For the cake, preheat the oven to 325°F. Grease and flour a 10-inch cake pan with 3-inch tall sides and line the bottom with parchment paper.
2. In a stand-up mixer or in a large bowl with electric beaters, beat the butter and sugar until fluffy. Add the eggs one at a time, mixing well after each addition, and stir in vanilla.
3. In a separate bowl, sift the flour, baking powder and salt. Add the flour to butter mixture in 4 additions, alternating with the milk and blending well after each addition, starting and ending with flour.
4. Melt the chocolate in a bowl over barely simmering water, stirring until almost melted. Remove from the heat and continue to stir until melted. Pour the warm white chocolate into the cake batter while blending until incorporated.
5. Pour the batter into the prepared pan and bake until a tester inserted in the center of the cake comes out clean, about 45 minutes. Allow the cake to cool 30 minutes, then remove from pan to cool completely. Wrap cake and store frozen or at room temperature until ready to assemble.
6. For the buttercream, beat the butter until fluffy. Beat in the cooled melted chocolate on medium speed. Reduce the speed and beat in the icing sugar, vanilla and salt (icing will be a little soft). Chill for about an hour to set before using. (The buttercream can be made ahead and chilled for up to a week, or wrapped and frozen up to a month (thaw refrigerated). Once thawed, beat to
make fluffy, then use.)
7. To assemble, slice cake horizontally into three layers. Spread about ⅔ cup of icing on bottom layer, and spread ⅓ cup of icing on next layer. Sprinkle mixed berries over iced bottom layer and place next layer on top, with iced-side down, so that icing holds berries in place. Repeat with next layer. Ice outside of cake on top and sides to cover and level. Use any remaining frosting to pipe details on the top of the cake, a desired. Chill until ready to serve.