01 - Preheat the oven to 350°F and lightly grease a standard donut pan with cooking spray or butter.
02 - In a large mixing bowl, whisk together sweet rice flour, granulated sugar, baking powder, and sea salt until evenly distributed.
03 - In a separate bowl, beat the eggs thoroughly, then whisk in milk, melted butter, fresh lemon juice, lemon zest, and vanilla extract until smooth.
04 - Pour the wet mixture into the dry ingredients. Stir gently until just combined and the batter is smooth, being careful not to overmix.
05 - Transfer the batter to a piping bag or zip-top bag with a corner snipped off. Pipe the batter evenly into the prepared donut pan, filling each cavity about 3/4 full.
06 - Bake for 18-20 minutes until the donuts are puffed and lightly golden. A toothpick inserted into the center should come out clean.
07 - Allow the donuts to rest in the pan for 5 minutes, then carefully transfer to a wire rack to cool completely before glazing.
08 - Whisk together powdered sugar, lemon juice, and lemon zest until smooth and pourable. Adjust consistency with additional juice if needed.
09 - Dip the tops of the cooled donuts into the glaze, allowing excess to drip off. Place on a wire rack and let the glaze set for about 10 minutes before serving.