In a large bowl whisk flour, sugar, baking powder and salt. Add in cold butter cubes and using a fork, or pastry cutter work the flour mixture.
Fold in blueberries and lemon zest and set aside.
Pour wet mixture into dry mixture and using a spoon mix just until combined.
Sprinkle some flour on a surface and lay out dough. Gently form into an 8 inch disk. Using a sharp knife cut the disk into 6 wedges. Place on baking sheet.
Brush the top with the 2 tablespoons heavy cream
Bake 18-20 minutes