If you like peanut butter, you're going to love this Peanut Butter Sheet Cake. It's easy to make and so wonderfully tasty! I even topped it with peanut butter eggs for an added treat!
Begin by preheating your oven to 350 degrees F. Spray a 10x15x1-inch cookie sheet (jelly roll pan) with baking spray. Set aside.
In a large bowl, whisk together the flour, sugar, baking soda, and salt. Set aside.
In a large saucepan, combine the butter, water, and peanut butter. Bring to a boil. When it begins to boil, immediately remove it from the heat and pour it over the flour mixture. Start to combine, then add the milk, vanilla, and eggs. Mix with a spatula or spoon until incorporated.
Pour the batter into the prepared cookie sheet. Bake for 20 minutes at 350 degrees F. Remove from the oven and allow to cool until just slightly warm.
For the frosting, add the butter, peanut butter, milk, and a pinch of salt to a sauce pan. When this mixture begins to boil, remove it from heat. Add the confectioners' sugar and mix to combine. (If needed, add more milk, one teaspoon at a time, to achieve the desired consistency.) Pour the warm frosting over the cooled cake and spread evenly with a spatula. Allow the frosting to cool before serving. Garnish with peanut butter eggs, if desired.