Preheat oven to 350 degrees.
In a large mixing bowl, combine the flour, sugar, and baking powder.
Add the egg, milk, coconut oil, vanilla, lemon juice, and zest and stir well to combine.
Transfer dough into a piping bag and pipe the dough into the donut pan, filling 3/4 of the way to the brim with batter.
Bake for 10-12 minutes or until toothpick inserted into donut comes out clean. Transfer donuts to a cooling rack.
Before shutting off the oven, spread the coconut flakes out on a sheet pan. Bake for just 3-5 minutes or until golden brown and fragrant. Set aside to cool.
While the donuts are baking, prepare the glaze by mixing powdered sugar, juice, and zest together in a bowl with a whisk.
Once donuts have cooled off, dip each donut into the lemon glaze. Sprinkle with toasted coconut.