01 -
2 cups all-purpose flour.
02 -
2 cups granulated sugar.
03 -
¾ cup dutch-processed cocoa powder.
04 -
1½ teaspoons baking soda.
05 -
1 teaspoon baking powder.
06 -
1 teaspoon kosher salt.
07 -
2 large eggs plus 2 yolks, room temperature.
08 -
½ cup vegetable oil.
09 -
½ cup unsalted butter, melted.
10 -
¾ cup sour cream, room temperature.
11 -
¼ cup whole milk, room temperature.
12 -
1 cup hot coffee or water.
13 -
½ cup hazelnuts, chopped.
14 -
1⅓ cups Nutella, divided.
15 -
½ cup heavy cream, divided.
16 -
¾ cup unsalted butter, room temperature.
17 -
3 cups powdered sugar.
18 -
1 teaspoon vanilla.