Step 1

Preheat oven to 400°F. Grease a large cookie sheet or line with parchment paper.

Step 2

Mix together dry ingredients: flour, sugar, baking soda, and salt. Set aside.

Step 3

Whisk together ½ cup milk, vanilla extract, eggs. Set aside.

Step 4

In a saucepan, melt 1 cup (2 sticks) of butter and 1 cup peanut butter, bring to a boil. Remove from heat and slowly add flour mixture, followed by milk and egg mixture. Mix until well combined.

Step 5

Pour batter onto cookie sheet, spreading batter evenly to edges. Bake for 20 minutes or until toothpick inserted in center comes out clean. Cool completely before frosting.

Step 6

For frosting: In a saucepan, bring 1 stick butter and ½ cup peanut butter to a boil. Add 2 tablespoons milk and slowly mix in powdered sugar until well combined. Pour frosting over cake, spreading evenly to edges. Allow frosting to cool and set before serving.