If you're a fan of peanut butter and all things cake, then Peanut Butter Texas Sheet Cake is for you. This delicious treat combines the rich, nutty flavor of peanut butter with a moist and fluffy cake base, topped with a creamy peanut butter frosting.
Preheat oven to 350°F. Prepare a half sheet pan (18x13") or jelly roll pan (15x10").
Combine butter, water, and peanut butter in a small saucepan on the stovetop and bring to boil.
In large mixing bowl or stand mixer bowl, combine flour, granulated sugar, baking soda, and salt. Pour the peanut butter mixture over the flour mixture in the mixing bowl, until well combined, but do not overmix. Add buttermilk, vanilla extract, and eggs, then mix until no lumps.
Make the frosting when the cake has about 5-10 minutes to go. In a saucepan, boil butter, peanut butter, and milk. Remove from heat and stir in vanilla extract.