Preheat oven to 350 degrees. Grease a 24-count mini muffin pan with non-stick cooking spray.
In a medium bowl, whisk together the gluten free flour, baking powder, baking soda, salt, and cinnamon. Set aside.
In a large mixing bowl, use an electric hand mixer to cream together the butter and sugar until light and fluffy (3-4 minutes).
Mix in the egg, milk, sour cream, and almond extract until combined.
Add ½ the dry ingredients to the wet ingredients and mix until just combined. Mix in the remaining dry ingredients until just incorporated.
Use a 1.5 tablespoon scoop to spoon the batter into each muffin cup, filling ¾ full.
Bake at 350 degrees for 9-11 minutes, or until a toothpick inserted into the center of a donut hole comes out clean.
Cool the donut holes in the pan for 5 minutes before removing them to a wire rack to cool completely.
Make the Glaze:
In a medium mixing bowl, add the powdered sugar, almond extract, and 3 tablespoons of milk. Stir together with a spoon until the mixture is smooth. Add the additional ½ tablespoon of milk, if necessary, to achieve the desired consistency.
Place the cooled donut holes, two at a time, in the bowl of glaze. Using two spoons, coat the donut holes with glaze.
Transfer the glazed donut holes to a wire rack, placed over a baking sheet, to allow the excess glaze to drip off.
Use a 1.5 tablespoon cookie scoop to transfer the batter to the mini muffin cups. The cookie scoop makes the process quick and easy. If you don’t have a cookie scoop, you can place the batter in a plastic bag. Cut the corner off the plastic bag and squeeze the batter into the muffin cups.
Set the freshly glazed donut holes on a wire rack placed over a baking sheet. Doing this allows the excess glaze to drip on to the pan and not your counter. If you set the glazed donuts on parchment paper or paper towels, the bottoms will get mushy.