1Make the chocolate simple syrup by heating a half a cup of water and a half a cup of granulated sugar until the sugar is fully dissolved.
2Mix in a tablespoon of dark cocoa powder.
3Pour into a jar to cool.
4Whisk together all the dry ingredients: 2 cups all-purpose flour, 2 cups granulated sugar, ¾ cup dark cocoa powder, 2 teaspoons baking powder, 1 ½ teaspoons baking soda, and 1 teaspoon fine salt.
5Combine 1 cup warm water, 1 cup sour cream, ½ cup vegetable oil, 2 large eggs, 2 teaspoons vanilla extract, and 1 teaspoon instant espresso.
6Pour the wet ingredients into the dry and whisk together until smooth.
7Pour batter into lined and greased cake pans.
8Bake at 350°F for 22 to 26 minutes.
9Make the chocolate frosting.
10Mix together 2 cups unsalted butter, 1 cup dark baking cocoa, 1 teaspoon vanilla extract, and ½ teaspoon salt.
11Mix in 5 cups powdered sugar and ¾ cup heavy cream on low speed.
12Mix in 1 ⅓ cups of dark chocolate that’s been melted and cooled.
13Brush the cake layers with chocolate simple syrup and spread on an even layer of the chocolate frosting.