Preheat the oven to 350℉/176℃ and grab enough donut pans to make 12 donuts. (I use 2 pans of 6 donuts each.)
Whisk together the flour, baking powder, and cinnamon in a medium mixing bowl. Then add the wet ingredients and stir until combined.
Divide the donut batter between the 12 donut tins and bake for 12-15 minutes. The donuts are ready when they are firm to the touch, but give a little when gently pressed. Remove from the oven and let them cool before glazing.
While the donuts are cooling, prepare the glaze. Combine the sugar, lemon juice, and milk (starting with 1 tablespoon) in a small bowl. Add a little more milk if needed.
Once cooled, dip the tops of each donut into the glaze, and place them glaze side up on a wire rack to let the glaze set. Enjoy!
Notes
Weigh your flour using a kitchen scale for the most accurate results. Scooping flour from a bag may result in too much flour being used and could alter the texture.
Use fresh and active baking powder. Once opened, baking powder begins to lose its effectiveness, so it's best to consume your baking powder within 6 months.
Allow your donuts to cool for 10-15 minutes before attempting to remove them from the pan. If the donuts are too hot, you risk breaking them.
Once transferred to a wire rack, let them continue to cool to room temperature before glazing them.
The nutritional information above includes 1 donut, with the glaze.