Prepare: Preheat oven to 325°F and coat a doughnut pan with non-stick baking spray.
Make crumb topping: In a small bowl, combine the melted butter, light brown sugar, all-purpose flour, and cinnamon. Mix with a fork until crumbs form and set aside.
Combine dry ingredients: In a medium bowl, sift together the all-purpose flour, baking powder, cinnamon, and salt. Set aside.
Mix batter: In a mixing bowl, cream together the sugar, egg, and butter. Add the milk and vanilla extract. Slowly add the dry ingredients, mixing until the donut batter is just combined.
Fill pan: Transfer batter to a Ziploc or disposable piping bag, cut off the end, and pipe into the greased donut pan. Divide the crumb topping evenly over the tops of the donuts.
Bake: Bake for 15-17 minutes. Remove from the oven and cool for a few minutes before transferring to a cooling rack.
Glaze: In a small bowl, combine the powdered sugar, vanilla extract, and milk. Drizzle the vanilla glaze over the cooled donuts and serve.
Notes
Don’t overmix the batter. Mix just until the dry and wet ingredients are combined.
Let the donuts cool slightly before adding the vanilla glaze so it doesn’t melt off.
This recipe makes 6 donuts. For 12 donuts, double the recipe and use two doughnut pans.
Store leftovers in an airtight container at room temperature for up to 2 days or refrigerate for up to 5 days.
Donuts can be frozen for up to 2 months. For best results, freeze before glazing and add the glaze after thawing.