In a large bowl, whisk together the flour, baking powder, salt, and sugar.
With a pastry blender or two forks, cut in the cold cubed butter until pea-sized pieces remain. Stir in the chocolate chips.
Pour the heavy cream in slowly, gently mixing until the dough is moist and begins to come together. Remove the dough from the bowl and place it on a lightly floured surface. Gently knead the dough until it comes together and shape into a flattened disk.
With a bench scraper portion the dough into 8 wedges. Place the wedges of dough onto a parchment-lined baking sheet. Refrigerate the scones for 30 minutes.
While the scones are chilling, preheat the oven to 400°F. In a small bowl, whisk together the egg and tablespoon of heavy cream. Brush the egg wash onto each scone, you will not use all of the egg wash. Sprinkle each scone with granulated sugar.
Bake the scones for 20 minutes, or until golden brown.
Store the scones in an airtight container at room temperature for up to 3 days.