• To prepare the crumb topping, melt butter in small sauce pot
  over low heat, stirring constantly to prevent burning. Add brown sugar and stir
  until smooth.
• Whisk gfJules Flour, cinnamon and salt together in then add to saucepot, stirring to mix into the butter-sugar mix. Stir occasionally while cooking the mix. The mixture will be crumbly and dry with some chunks larger than others.
• Set aside to cool after five minutes of cooking.
• To make the gluten free donuts, preheat the oven to 350°F.
• Butter or oil a donut pan well.
• Whisk together dry ingredients: gfJules Flour; sugar; baking powder; baking soda; salt; nutmeg.
• To a mixing bowl, add the liquid ingredients: oil; yogurt; milk; egg; vanilla.
• Stir dry ingredients into the mixing bowl to combine. If using a stand mixer, I prefer using a flat paddle attachment. Beat until the batter is smooth, only about 1-2 minutes on medium speed; do not overmix. The batter should be slightly thicker than pancake batter.
• Transfer batter into a quart or gallon plastic bag then cut a small corner out. Use that corner to pipe batter equally into donut pans or  simply spoon batter into pans instead. If any extra batter remains, spoon into muffin cups to bake. With my donut pan, this recipe made 6 donuts and two muffins.

There are two options at this point:

• Either sprinkle the crumb topping on top of the batter in the donut pans (or on top of the muffins) before baking OR bake the donuts and then make the glaze after they cool; the crumb topping will stick to the glaze.
• Either way, place pans in the preheated oven on the middle rack and bake for 12-13 minutes, testing with a toothpick, removing the donuts when the toothpick comes out clean. Be careful not to over-bake, though. The donuts should also spring back when pressed with a gentle touch.
• Remove to cool on a wire rack.
• If making the glaze, make it while the donuts cool.
• To make the glaze, measure out the confectioner’s sugar and pour into a flat-bottomed bowl. If not already sifted, whisk the confectioner’s sugar at this point to remove lumps. Add vanilla and milk, whisking to make a smooth glaze. The consistency should not be too thin, but should be thin enough to be able to swirl the donuts through the glaze easily. If it’s too thin, add more confectioner’s sugar; if too thick, add more milk (only a tablespoon at a time).
• Once cooled, swirl the donuts through the glaze in the flat-bottomed bowl – only the tops are necessary, but you’re welcome to dip both sides if you like – then gently press down onto the crumb topping you’ve set aside. Set them back onto the wire rack to allow the glaze and crumbs to
  set.
• I recommend only doing one donut first, in case your glaze is too thin and the crumbs start to slide off; you’ll notice this right away with the first donut and you can stir extra confectioner’s sugar into the glaze to thicken it and correct the issue before it happens to all the donuts!
• Dust with more confectioner’s sugar before serving if you like.