1. Whisk together the cake flour, sugar, baking powder and salt into a large bowl. Add in the lemon zest and whisk this into your dry ingredients. Add the milk, eggs, softened butter and vanilla extract. Gently mix the ingredients together. Make sure not to overmix the batter.
2. Fold in the halved blueberries carefully. Lightly grease a doughnut pan with shortening using a paper towel to wipe around the insides. Spoon the batter into the doughnut pan, filling each one halfway. Bake the doughnuts at 400 F for 8-9 minutes. You’ll know they’re done when they spring back when you press them with your finger. Note: The donuts won’t brown, so take your cue from how they feel when you press them.

For the glaze

1. Put the powdered sugar in a large bowl. Add in the lemon juice, milk and vanilla extract. Whisk to combine. If the glaze is too thick, add just a bit of milk at a time. If it is too thin, add powder sugar until desired consistency is reached.