Preheat the oven to 350°F. Grease the 9"x 13" pan with butter or baking cooking spray.
In a bowl: add fresh blueberries (if using frozen do not thaw), sugar, lemon zest, flour and mix everything together. Transfer to the baking pan.
In a separate bowl: combine flour, salt, baking powder, sugar and mix. Add butter pieces into the bowl. Use a dough blender, your fingers or a fork to blend the flour mixture and butter together until pea size crumbs. Pour heavy cream into the mix and combine until everything comes together. It's going to be very sticky.
Coat the cutting board or parchment paper with 2-3 tsp of flour. Place dough on the board and shape into a rectangle 8"x 12". Place the dough on top of the blueberries.
Brush the scones with 2 tbsp heavy cream.
Bake for 35-40 minutes or until golden brown. Remove from the oven and let cool for 15 minutes before serving.