American Mud Cake with Sour Cream Chocolate Frosting

INGREDIENTS

1 cup

unsalted butter (2 sticks, or 8 ounces, or 227 grams) each halved

7 oz

72% cacao or more dark chocolate, chopped or broken coarsely (I used Ghiradelli Twilight Delight)

2 cups

(14 ounces, or 397 grams) granulated sugar

1/2 cup

(2 ounces, or 57 grams) Dutch processed cocoa powder (I recommend Cacao Barry Extra Brute or Pernigotti)

1 1/4 cups

strong hot coffee or hot water plus 1 tablespoon espresso powder

1 tbsp

vanilla extract

large eggs

2 cups

(10 ounces, or 284 grams) all-purpose flour

1 tsp

baking powder

1 1/2 tsp

baking soda (sodium bicarbonate)

1/2 tsp

salt

1/2 cup

(4 ½ ounces, or 128 grams by weight) sour cream

1/2 cup

(3 ½ ounces, or 100 grams) granulated sugar

1/2 cup

by weight, or 150 grams) corn syrup

1 tbsp

vanilla extract

1 1/2 cups

(12 ounces, or 3 sticks, or 340 grams) unsalted butter, softened

1 cup

(3 ½ ounces, or 100 grams) Dutch processed cocoa powder

4 cups

(16 ounces, or 454 grams) powdered sugar