# What You'll Need:
→ Cake
01 - 2 cups all-purpose flour
02 - 2 cups granulated sugar
03 - 1/2 teaspoon salt
04 - 1 teaspoon baking soda
05 - 1/2 teaspoon ground cinnamon (optional)
06 - 1 cup unsalted butter (2 sticks)
07 - 1 cup water
08 - 1/4 cup unsweetened cocoa powder
09 - 2 large eggs
10 - 1/2 cup sour cream
11 - 1 teaspoon vanilla extract
→ Fudgy Icing
12 - 1/2 cup unsalted butter (1 stick)
13 - 1/4 cup unsweetened cocoa powder
14 - 1/3 cup whole milk
15 - 3 1/2 cups powdered sugar, sifted
16 - 1 teaspoon vanilla extract
17 - 1 cup chopped pecans or walnuts (optional)
# How to Make It:
01 - Preheat oven to 350°F. Grease and flour a 13x18-inch rimmed baking sheet.
02 - In a large bowl, whisk together flour, sugar, salt, baking soda, and cinnamon if using.
03 - In a medium saucepan, combine butter, water, and cocoa powder. Bring to a gentle boil over medium heat, stirring until smooth.
04 - Pour the hot butter mixture over the dry ingredients and stir until well combined.
05 - In a small bowl, whisk together eggs, sour cream, and vanilla extract. Add to batter and mix until smooth.
06 - Pour batter into prepared pan, smooth the top, and bake for 18 to 20 minutes until a toothpick inserted in the center comes out clean.
07 - While cake bakes, melt butter with cocoa powder and milk in a saucepan over medium heat, stirring until smooth and just boiling. Remove from heat.
08 - Immediately whisk in powdered sugar and vanilla extract until smooth. Stir in nuts if desired.
09 - Pour warm icing over the hot cake as soon as it comes out of the oven, spreading quickly with an offset spatula.
10 - Allow the cake to cool at room temperature until icing is set. Cut into squares and serve.