Line a baking tray with parchment paper. Pulse the flour, sugar, baking powder and salt in a food processor, until fully combined. Add the butter and continue pulsing until it is roughly combined. There will still be lumps of butter. Tip the mixture into a bowl, and stir in the 2 eggs and cream with a knife. Gently mix in the blueberries with your hands.
Turn the dough out onto a lightly floured surface and press it into a 6 by 6-inch square pan. Cut the pastry into quarters, then halve each quarter. Place the pan onto the prepared baking tray and brush the scones with the egg and milk glaze. Bake for 15 to 20 minutes, or until golden. Serve warm with butter, if you like.
Tossing the blueberries in a bit of flour first prevents them all from sinking to the bottom of the dough.