Preheat the oven to 350 degrees.
Spray a donut tin (6 donuts) with cooking spray; set aside.
Place 1/4 cup of butter in the bowl of a stand mixer; beat until smooth. Scrape the sides of the bowl.
Add 1/2 cup sugar to the butter and cream together.
Add in the egg and apple butter; mix until smooth.
Sift together 1 cup of gluten free flour, 1/2 teaspoon cinnamon, and baking powder.
Add the dry ingredients into the wet. Mix until just combined.
Evenly distribute the batter among the 6 donut spots. You can do this with a small spoon, or you can place the batter into a piping bag or a resealable bag (with the end snipped off), and pipe the batter into each spot. If you use a bag be sure to cut a large end portion off the bag so the batter is piped out in a wide tube. If using a pastry bag, use a large, open tip.
Set the donut tin aside.
Cut 2 tablespoons of butter into small chunks. Place into a bowl along with the remaining gluten free flour, sugar, and cinnamon. Work all of the ingredients together until small crumbs form. You do not want sandy crumbs, but you also do not want huge crumbs. See photo.
Evenly distribute the crumbs among the 6 donuts. Very lightly press the crumbs slightly into the batter. You do not want to submerge the crumbs; you simply want them to make contact with the batter so the crumbs will adhere to the donut as it bakes.
Bake for 12-15 minutes.
Remove the donuts from the tin and place onto a cooling rack.
Once cool, place 1 tablespoon of powdered sugar into a handheld sifter. Sift the sugar over the tops of the donuts.