2-4 Tablespoons lemon juice (depending on whether you want a thick frosting, or a thin glaze)
Preheat your oven to 375°F. Lightly grease a Doughnut Pan.
In a large bowl, whisk together all of the dry ingredients, minus the granulated sugar.
Combine the granulated sugar and lemon zest in a small bowl. Using your fingers, rub the sugar and zest together, releasing the oils into the sugar, giving you a better lemon flavour. Add to dry ingredients, and whisk to combine.
In a smaller bowl, whisk together all of the wet ingredients.
Pour the wet ingredients into the dry ingredients and stir until fully combined.
Spoon mixture into a large resealable plastic bag. Cut the corner off, and pipe the batter into the prepared doughnut pan.
Bake in preheated oven for 12-14 minutes, or until a toothpick inserted into the thickest part of the doughnut comes out clean.
Let doughnuts sit for 5 minutes before turning them out onto a cooling rack. Allow to cool completely before frosting.
In a small bowl, whisk together all the ingredients until smooth.
If using a thin glaze, dip the doughnuts into the glaze while they are still hot. Set on a cooling rack over a sheet of waxed paper to cool.
If using a thicker frosting, wait until doughnuts are completely cool before frosting.
Store doughnuts in an airtight container on the counter for up to 3 days.
Recipe by The Baking Beauties at http://www.thebakingbeauties.com/2013/03/gluten-free-baked-lemon-doughnuts.html