Preheat the oven to 350 degrees.
Prepare 3 nine-inch cake pans by placing parchment paper circles in the bottoms of the pan and then spraying the sides of the cake pan with non-stick cooking spray. OR you can grease and flour the cake pans. Set aside.
Sift the flour, cornstarch, and baking powder together twice. Set aside.
In a large mixing bowl, cream the 12 Tbs. butter, sugar, salt, and vanilla bean paste for 4 minutes.
Beat in the egg whites.
Scrape down the sides of the bowl.
Beat in ⅓ of the sifted flour mixture.
Beat in ½ of the half and half.
Beat in another ⅓ of the flour mixture.
Beat in the remaining half and a half.
Beat in the remaining flour mixture.
Beat at a medium speed for a full 2 minutes.
Divide the batter among the prepared baking pans.
Spread and smooth the batter.
Bake at 350 degrees for 25-27 minutes.
Cakes should be golden brown, and a toothpick should come out clean.
Cool cakes for at least 20 minutes before loosening the sides and turning them out on a wire rack to finish cooling.
While the cakes bake and cool, make the white chocolate cream cheese frosting.
In a large mixing bowl, beat the butter and cream cheese until completely smooth.
Carefully melt the white chocolate just until melted and smooth.
Pour the white chocolate into the cream cheese/butter mixture while beating at a high speed.
Beat in the vanilla and powdered sugar. FYI...this is not a stiff frosting.
Once the cakes are cool, place the first layer on a cake plate.
Spread ½ the raspberry jam evenly over the cake layer.
Dot some frosting over the jam and spread it into an even layer.
Place this layer in the freezer for 15 minutes to set the frosting.
Remove from the freezer and top with another layer of cake.
Evenly spread the remaining jam on the top of this layer, followed by white chocolate frosting as before.
Place in the freezer for 15 minutes.
Remove from the freezer and place the remaining cake layer on the top.
Frost the entire cake, filling in the gaps between the layers and a thin layer around the sides and on the top. (AKA crumb layer)
Pop in the freezer for 10 minutes.
Remove from the freezer and frost the cake evenly with the remaining frosting.
Put in the fridge this time until you're ready to serve the cake.
You can garnish this cake with fresh raspberries and mint leaves if desired.
Store leftover cake in the fridge.