Whisk all purpose flour, almond flour, granulated sugar, lemon zest, salt, and baking powder. Add diced frozen butter and coat with dry mixture.
Create a well and add butter milk, an egg and vanilla.
Mix into almost incorporated. Add blueberries. Mix gently until incorporated.
Spray a parchment lined baking sheet with non stick baking spray.
Add mixture to the center and form into a circle.
Using a knife or bench scraper, cut 8 slices, but not all the way through. Brush with eggwash or milk
Bake in 400 degree oven for 12-15 mins or until golden brown Remove from oven and let rest for 5-10 mins.