Chocolate Hazelnut Cake with Nutella Buttercream (Print Version)

# Ingredients:

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.

# Instructions:

01 - Heat oven to 350°F. Grease two 8-inch cake pans and line bottoms with parchment.
02 - Whisk dry ingredients. Combine wet ingredients separately. Mix together, add hot coffee last. Divide between pans.
03 - Bake 30-35 minutes until toothpick comes clean. Cool 10 minutes in pans, then remove and cool completely.
04 - Toast hazelnuts until golden. Cool and chop. Whip Nutella with cream, fold in nuts.
05 - Beat butter and Nutella until fluffy. Add sugar, cream, vanilla, and salt. Beat until smooth.
06 - Level cakes. Fill with hazelnut mixture. Crumb coat, chill, then final coat with buttercream.

# Notes:

01 - Use room temperature ingredients for best results.
02 - Keeps at room temperature 1 day, refrigerated 2-3 days.