Preheat your oven to 400°F (200°C) and line a baking tray with parchment paper.

In a large bowl, whisk together the flour, granulated sugar, baking powder, and salt.

Add the cold, cubed butter to the flour mixture and use a pastry cutter to work the butter in until the largest pieces are the size of small peas.

Gently fold in the chocolate chunks using a rubber spatula.

In a separate small bowl, whisk the heavy cream, egg, and vanilla extract until combined.

Pour the wet mixture into the dry ingredients and stir just until a shaggy dough begins to form; do not overmix.

Turn the dough onto a lightly floured surface and pat it into a 1-inch thick circle.

Use a sharp knife to cut the circle into 8 equal wedges, similar to a pizza.

Place the wedges on the prepared baking tray, leaving at least 2 inches between each one.

Brush the tops with the remaining tablespoon of heavy cream and sprinkle with coarse sugar.

Bake for 18 to 22 minutes, or until the tops are golden brown and a toothpick inserted into the center comes out clean.

Transfer to a wire rack to cool for at least 10 minutes before serving.