Preheat oven to 450°F (232°C) with the rack on the middle shelf.
Add the flour, sugar, baking powder, and salt to a food processor. Pulse a few times to mix.
Scatter the cold butter across the flour. Pulse until it resembles cornmeal or wet sand, approximately 10-12 pulses.
Pour out the flour mixture into a bowl. Add the blueberries and heavy cream. Mix until just barely incorporated. Do not overmix (a little dry mixture is okay and preferred to overmixing).
Spray a cake pan with nonstick spray.
Dump the dough into the cake pan and press into an even layer.
Refrigerate the dough in the pan for 30 minutes (or longer, see note).
After chilling, remove the pan from the refrigerator and slam onto the counter or cutting board. Repeat if needed until the dough disk falls out.
Using a sharp knife, cut the disk in half, then half again in the opposite direction to give you four quarters. Then cut each piece in half again (think like a pizza) to give you 8 triangles.
If desired, coat with the melted butter and sprinkle with additional sugar for texture and color.
Place the scones on a lined baking sheet.
Bake for 13-15 minutes until lightly golden brown. Rotate the baking sheet halfway through baking. Cool on a wire rack for at least 10 minutes. Drizzle with lemon glaze if desired when cool. Store in a sealed container for up to 5 days.
Scones can be covered and refrigerated up to 24 hours before baking, after cutting or after put into cake pan.Freeze the scones after cut and before baking for up to a month. Then bake as desired and directed in instructions, without thawing, although you may need to bake them a few minutes longer.Frozen blueberries can be used in place of fresh. Just thaw and drain before using.Refrigerating for 30 minutes is highly recommended as it helps the scones rise instead of being wide and flat.