7-8tbsfresh lemon juice or milk(depending on your tastes)
Preheat oven to 425 degrees F and grease your doughnut pans with butter or non-stick spray.
Blend blueberries and milk together until smooth.
In a large bowl, combine butter, oil and sugar and whisk until smooth and fluffy, about 2 minutes.
Add in eggs, vanilla, lemon zest and whisk until smooth.
Add flour, baking powder, baking soda and salt, and whisk just until combined. Stir in blueberries puree and fresh blueberries.
Spoon better into donut pan – the batter shouldn’t quite fill the hole as they’ll expand and rise.
Bake for 7-8 minutes until a toothpick inserted comes out clean. Let cool 10 minutes before removing from the donut pan to cool completely.
In a medium bowl (not too deep as you’ll want to be able to dip your doughnuts), combine sugar, zest, and 6 tbsp of juice or milk. Add an additional 1-2 tbsp of liquid if needed. You want your glaze to be thin enough to evenly coat your donuts, but thick enough that it will set and become dry to the touch.
When donuts are completely cool, dip tops of doughnuts into the glaze and overturn so the glaze runs down the sides. Set aside for the glaze to set. Enjoy