1. Preheat oven to 350 degrees. Prepare a mini or regular size donut pan with non stick spray. If you do not have a donut pan, you can also use a mini or regular size cupcake pan. Just add a minute or two to the baking time.
2. In a large bowl, add the the egg, sugar, Greek yogurt (or sour cream), oil, lemon zest, lemon extract and food coloring (optional). Whisk together until combined. Note- do not use lemon juice or oil. Lemon juice is too acidic and will change the dough and lemon oil is way too potent.
3. Add the flour, baking powder, baking soda, salt, and stir gently with a spatula until just combined. Careful not to overmix.
4. Using a spoon or piping bag, fill each donut 3/4 full. Bake mini donuts for 10 minutes and regular size donuts for 11-12 minutes. They should be springy to the touch.
5. Once done, place on cooling sheet to cool while making the glaze.