01 - Preheat the oven to 350°F. Lightly grease a 12-cavity donut pan with cooking spray or butter.
02 - In a large bowl, mash the bananas until smooth. Whisk in melted butter and brown sugar until fully incorporated and mixture is creamy.
03 - Add eggs, milk, and vanilla extract to the banana mixture. Whisk until smooth and uniform in texture.
04 - In a separate medium bowl, whisk together flour, baking powder, baking soda, cinnamon, nutmeg, and salt until well blended.
05 - Gradually fold dry ingredients into wet mixture using a spatula. Mix until just combined—do not overmix as this will toughen the donuts.
06 - Spoon or pipe batter into prepared donut pan, filling each cavity about 3/4 full. A piping bag or zip-top bag with corner snipped works best for even distribution.
07 - Bake for 10–12 minutes until donuts are golden and a toothpick inserted into the center comes out clean.
08 - Let donuts rest in pan for 5 minutes, then carefully transfer to a wire rack to cool completely before glazing.
09 - In a small bowl, whisk powdered sugar, milk, and vanilla until smooth and drizzle-consistency. Dip tops of cooled donuts into glaze or drizzle over using a spoon.