01 - Preheat the oven to 350°F. Lightly grease a standard donut pan with cooking spray or butter.
02 - In a large bowl, whisk together sweet rice flour, granulated sugar, baking powder, and salt until evenly blended.
03 - In a separate bowl, beat the eggs thoroughly. Whisk in milk, melted butter, lemon juice, lemon zest, and vanilla extract until smooth.
04 - Pour the wet mixture into the dry ingredients. Stir gently until just combined and smooth, being careful not to overmix.
05 - Transfer the batter to a piping bag or zip-top bag. Pipe the batter into the prepared donut pan, filling each cavity approximately 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 - Let the donuts cool in the pan for 5 minutes, then carefully transfer to a wire rack to cool completely before glazing.
08 - Whisk together powdered sugar, 2 tablespoons lemon juice, and lemon zest until smooth and pourable. Add additional lemon juice if needed to reach desired consistency.
09 - Dip the top of each cooled donut into the glaze, allowing excess to drip off. Return to the wire rack and let the glaze set for about 15 minutes before serving.