Preheat oven to 350°F. In a large bowl, combine oats, brown sugar, granulated sugar, baking powder, and salt. In a separate bowl, whisk together milk, melted butter, peanut butter, vanilla, and egg. Pour wet ingredients into dry ingredients and mix until fully combined.

Pour the mixture into a greased 8x8 inch baking dish and spread evenly.

Bake for 20-25 minutes until golden brown around the edges and a toothpick inserted in the center comes out clean.

Allow to cool slightly before serving. Serve warm with your favorite toppings.