Preheat the oven to 400 degrees. Line a small sheet pan with parchment paper. Spray the parchment with pan spray and set aside.
In a large bowl, sift together the flour, baking powder, and sugar. Whisk in the salt.
Toss in the blueberries and coat with the flour mixture.
Grate the butter into the flour mixture and lightly mix with a wooden spoon to combine.
Pour in the milk. Mix with a wooden spoon to incorporate. Then use your hands to thoroughly mix.
Dump the dough onto the parchment lined sheet pan. Flatten the dough to the size of the pan. With a butter knife or dough cutter, slice the dough into 9 even pieces.
Bake for 20 minutes, rotating halfway through baking.
Let cool for 5 minutes before adding lemon glaze.