Preheat oven to 400 degrees.

Place flour, sugar, baking powder, and salt in a bowl and whisk. Grate in the cold butter and incorporate into the flour mixture with your hands.

In a separate bowl, whisk sour cream, espresso, and egg together and then pour into the flour butter mixture. Mix together until it forms a ball. Fold in the chocolate chunks. Cut the dough in half and roll each half into a ball. Place each dough on a baking sheet and flatten out into one-inch thick disks. Cut each disk of dough into eight pieces like you’re cutting a pizza. 

Bake for 18 minutes and let cool about twenty minutes before glazing.

For the glaze, mix the powdered sugar, corn starch and espresso together. Add more powdered sugar if you’re not getting the consistency you like. Drizzle on top of scones then add a sprinkling of flaked sea salt to each scone.