Preheat the oven to 350°F (177°C). Grease three 9-inch round cake pans, line with parchment paper rounds, then grease the parchment paper. Parchment paper helps the cakes seamlessly release from the pans. (If it’s helpful, see this parchment paper rounds for cakes video & post.)

Whisk the flour, cocoa powder, sugar, baking soda, baking powder, salt, and espresso powder (if using) together in a large bowl. Set aside. Using a handheld or stand mixer fitted with a whisk attachment (or you can use a whisk) mix the oil, eggs, sour cream, buttermilk, and vanilla together until combined. Pour the wet ingredients into the dry ingredients, add the hot water or coffee, and whisk or beat it all until the batter is completely combined.

Divide batter evenly between 3 pans. Bake for 21-25 minutes. Baking times vary, so keep an eye on yours. The cakes are done when a toothpick inserted in the center comes out clean.

Remove the cakes from the oven and set on a wire rack. Allow to cool completely in the pan.

so it can cool and be ready at the same time. Place chopped white chocolate in a bowl. Heat the cream in a small saucepan until it begins to gently simmer. (Do not let it come to a rapid boil—that’s too hot!) Pour over white chocolate and stir until completely combined and chocolate has melted. Cover and refrigerate until it’s thick and a spreadable consistency, about 1-2 hours. You don’t want it runny.

In a large bowl using a handheld or stand mixer fitted with a paddle or whisk attachment, beat the butter on high speed until creamed, about 2 minutes. Add 4 cups confectioners’ sugar, the cocoa powder, milk/cream, corn syrup, vanilla, and salt. Beat on low speed for 30 seconds, then switch to high speed and beat for 2 minutes until combined and smooth. If you want the frosting a little thicker, add the extra 1/2 cup of confectioners sugar. (I add it.)

Place 1 cake layer on your cake stand, cake turntable, or serving plate. Evenly cover the top with 1/2 of the white chocolate ganache. Top with 2nd layer and evenly cover the top with remaining ganache (if there is too much ganache, serve a dollop/spoonful with each slice!). Top with the third cake layer. Spread the frosting into a thick layer all over the top and sides. Garnish with raspberries and mint, if desired. Refrigerate for at least 45 minutes before slicing or else the cake may gently fall apart as you cut.

Cover leftover cake tightly and store in the refrigerator for 5 days.