Preheat your oven to 425°F (220°C) and line a baking sheet with parchment paper.

In a large mixing bowl, combine the flour, baking powder, salt, and sugar. Whisk together until well blended.

Add the cold, cubed butter to the flour mixture. Use a pastry cutter or your fingers to work the butter into the flour until the mixture resembles coarse crumbs.

Gently fold in the blueberries, being careful not to crush them.

In a separate bowl, mix the buttermilk and vanilla extract. Pour this mixture into the dry ingredients and stir until just combined. Do not overmix.

Turn the dough out onto a lightly floured surface and gently knead it a few times until it comes together. Pat the dough into a 1-inch thick rectangle.

Cut out biscuits using a round cutter or a glass, and place them on the prepared baking sheet. Gather any scraps, re-knead gently, and cut out additional biscuits.

Bake for 12-15 minutes, or until the biscuits are golden brown on top.

Allow the biscuits to cool slightly on a wire rack before serving.