Peanut Butter Cookie Mug Cake - This cookie in a mug takes just a few minutes and tastes just like a peanut butter cookie! Perfect for when you just want a single serving of a dessert!
In a small bowl, combine flour, brown sugar, baking powder, and cinnamon.
Combine in vanilla, milk, peanut butter, and melted butter. Stir until combined with no lumps.
Pour batter into mug and microwave for 1-1:30 minutes.