Strawberry Chocolate Layer Cake

Instructions

1. For the strawberry ice cream, slice the strawberries if they are large, and place in a medium bowl. Toss with the sugar, and let sit at room temperature for at least 1 hour, stirring occasionally.
2. Place the strawberries, sour cream, heavy cream and lemon juice in a food processor or blender. Pulse until mostly smooth, but a few larger pieces remain. Refrigerate until chilled, then freeze in your ice cream maker according to the manufacturer's instructions.
3. To make the cake, heat the oven to 350ºF.  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.
4. With the mixer on low speed, pour in the buttermilk, oil and vanilla.  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.
5. 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.
6. To make the strawberry milk soak, place the strawberries and sugar in a blender or food processor. Let macerate for at least 1 hour, until juicy.  (You want a lot of juice to release from the strawberries.)  Blend the strawberries until completely smooth, about 1 minute.  Pour the strawberry mixture into a large pitcher and mix in the milk and buttermilk.  Stir well, then place in the refrigerator until ready to use.
7. To make the strawberry crumb, heat the oven to 250ºF.  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 small clusters form. Spread the clusters out on the baking sheet and bake for 20 minutes.  Remove from the oven and let cool completely.
8. Once the crumbs are cooled, place the freeze-dried strawberries in a food processor and mix until they are a fine powder.  Drizzle the melted white chocolate over the crumbs. Add in the strawberry powder, and stir thoroughly with a fork until well coated.  Let cool until the chocolate is set.
9. When you're ready to assemble the cake, make the ganache.  Place the chopped chocolate in a medium heat proof bowl.  Bring the cream to a simmer in a saucepan over medium heat.  Pour the hot cream over the chocolate and let stand about 2 minutes.  Whisk together until the chocolate fully melts and is smooth.  Let cool to room temperature.
10. 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 1/2 cup of the strawberry milk.  Spread 1/3 of the ganache over the cake.  Then, spread about 1 cup of ice cream over the cake.  Sprinkle with an even layer of the strawberry milk crumb (about one third), gently pressing down to adhere the crumbs to the ice cream.  Gently tuck a second strip of acetate between the cake ring and the top 1/4-inch of the first strip of acetate.  Set a cake round on top of the strawberry milk crumb, and repeat the layering process once more (milk soak, ganache, ice cream, strawberry milk crumb.)  Place the remaining cake layer onto top of the strawberry milk crumb. Top with a thin layer of the remaining ganache.  Sprinkle strawberry milk crumb over the top for garnish. 
11. Transfer the assembled cake to the freezer and freeze for a minimum of 12 hours to set the cake and the filling. At least 3 hours before you are ready to serve, remove the pan from the freezer, pop the cake out of the cake ring, and peel away the acetate layers. Transfer to a cake round and platter and defrost for at least 3 hours before slicing and serving.  Store covered, in the freezer.