Heat the oven to 400°F. Cooking spray a 12-count donut pan and set aside. Mix flour, baking powder, and salt in a large bowl.
Two teaspoons baking powder, half a teaspoon salt, two cups all-purpose flour Mix brown sugar, eggs, peanut butter, sour cream, milk, and vanilla in another large dish until smooth.
1/2 cup light brown sugar, 2 large eggs, 1/2 cup creamy peanut butter, 1/2 cup sour cream, 6 tablespoons milk, 2 teaspoons vanilla extract Stir the dry ingredients into the wet until no dry spots remain.
Divide the batter evenly in the 12-count donut tin and smooth the tops. Bake 9-10 minutes until puffed and lightly browned.
After 5 minutes in the pan, remove the donuts and finish cooling on a wire rack. After the donuts cool, blend powdered sugar, peanut butter, 3 tablespoons milk, and vanilla until smooth to make the glaze.
You want the glaze to be thick yet pourable, so add milk a little at a time. 2 cups powdered sugar, 2 tablespoons creamy peanut butter, 3-4 tablespoons milk, 1 teaspoon vanilla Dip the donut tops in glaze and drain excess.
Place glaze-side-up donuts on a wire rack over a sheet tray. Enjoy donuts after 30 minutes for the glaze to set.