Preheat oven to 325 degrees F. Spray a doughnut pan with nonstick cooking spray and set aside.

Prepare the crumb topping by melting the butter in a heatproof bowl. Stir in brown sugar, flour, and ground cinnamon until coarse crumbs form. Set aside.

In a medium bowl, sift together flour, baking powder, and salt. Set aside.

In the bowl of your stand mixer, cream together sugar, egg, and melted butter. Add milk and vanilla extract.

Once wet ingredients are combined, slowly add dry ingredients and mix until fully incorporated.

Spoon batter into a medium-sized Ziploc bag, seal, and cut off one corner of the bag. Fill each doughnut cup ? full. Divide crumb topping equally between the 6 donuts.

Place into the preheated oven and bake for 14-16 minutes or until donuts are slightly golden. Remove from oven and let rest in the doughnut pan for 5 minutes or until slightly cooled. Remove donuts and place on a wire rack.

Next, make the glaze by whisking together confectioner?s sugar and milk until smooth. Drizzle desired amount over donuts and enjoy!