Preheat oven to 350 degrees Fahrenheit. Take 3 9”x5” loaf pans and spray with non-stick baking spray. Line then with parchment paper.
To make chocolate cake batter, combine dry ingredients in a medium size bowl. Whisk to break up clumps. Add in melted butter, egg, then milk, and whisk until smooth. Pour batter into loaf pan and bake for 20minutes, or until a toothpick inserted comes out clean.
To make strawberry cake batter, chop strawberries into small pieces and place in a medium size bowl. Add in salt and sugar and mix to macerate. Leave strawberries in bowl for about 5 minutes to let the juices come out. Add in melted butter, milk, and egg white and mix until smooth. Add in dry ingredients next and mix until smooth. Pour batter into loaf pan and bake for20 minutes, or until a toothpick inserted comes out clean.
To make white cake, combine dry ingredients in a medium size bowl and whisk to break up any clumps. Add in melted butter, egg white, sour cream, and milk, and mix until smooth. Pour batter into loaf pan and bake for about 15 minutes, or until a toothpick inserted comes out clean.
Cool each cake at room temperature for 5 minutes, then freeze cakes in pans for 1 hour.
To make vanilla ermine buttercream, whisk sugar and flour in a small sauce pot. Add in milk and cream and whisk until smooth. Turn heat onto medium and cook while whisking until the mixture boils. Continue to cook for about 3-5 minutes. Once the mixture is as thick as a pudding, remove from heat and transfer to a small bowl. Cover the surface with plastic wrap and let it cool at room temperature for 1 hour, or until its no longer hot.
Place room temperature butter in a mixer fitted with a paddle attachment. Add in cooled custard. Paddle on medium high speed until light and fluffy. Add in vanilla and combine. Scrape down sides as needed.
To build the cake, place the chocolate cake on a serving dish or cake board. Scoop or pipe a layer of buttercream on top. Place white cake on next, then another layer of buttercream. Place strawberry cake on top. Cover the sides and top with more buttercream. Use an offset spatula to spread it around evenly. Chill cake while preparing the chocolate glaze.
To make chocolate glaze, sift powdered sugar and cocoa powder in a medium size bowl. Add in corn syrup, then milk, and whisk until smooth. Add in more milk if you’d like a looser glaze. Pour glaze over the top of the cake. To control the drip around the cake, you can pipe glaze on the top instead. Top the glaze with fresh strawberries.
Before serving, let the cake come to room temperature for 1hour. If you’re serving at a later time, chill the cake.