Peanut Butter Cake

Step 1
Gather all ingredients.

Step 2
Preheat the oven to 350 degrees F (175 degrees C). Grease a rimmed baking sheet.

Step 3
Make cake: Whisk together flour, sugar, and baking soda in a large bowl.

Step 4
Beat milk, eggs, and vanilla into flour mixture with an electric mixer on low speed until smooth.

Step 5
Place water, butter, oil, and peanut butter into a saucepan; cook and stir over medium heat until smooth, about 5 minutes.

Step 6
Stir peanut butter mixture into flour mixture until batter is well mixed; pour and spread onto the prepared baking sheet.

Step 7
Bake in the preheated oven until a toothpick inserted into the center of the cake comes out clean, about 20 minutes.

Step 8
Make icing: Melt butter and peanut butter in a saucepan over medium heat; stir until smooth.

Step 9
Mix in milk and vanilla until combined.

Step 10
Whisk in confectioners' sugar until icing is smooth, 3 to 5 minutes.

Step 11
Pour icing over warm cake and spread evenly.