Preheat the oven to 425℉. Lightly mist a baking sheet with cooking spray or line it with parchment paper; set aside.

To a mixing bowl, add the flour, baking powder, sugar, 1 teaspoon salt, and the baking soda; whisk together to combine.

Using a box grater, grate the cold butter into the flour mixture. If you don’t have a box grater, you can cut the cold butter up into very small pieces with a knife. Just be sure to work quickly and handle the butter as little as possible to prevent it from melting.

Use a fork or pastry blender to work the grated butter into the flour mixture until it resembles coarse crumbs. TIP: Avoid using your hands to mix, as this can cause the butter to melt and will not give you the fluffiest biscuits.

Make an indentation (or “well”) in the center of the flour mixture. Pour the milk and vinegar into the well and stir until a soft, craggy dough forms (rough and uneven with some lumps). NOTE: Not all of the flour will be incorporated into the dough.

Turn the dough and any loose bits of flour out onto a lightly floured flat surface.

Use your hands to quickly pat the dough into a rectangle that is 1-inch thick.

Working quickly, fold the rectangle of dough in half and then press it into a rectangle again.

Repeat this fold-and-press process 4 more times. By now all of the flour should be incorporated into the dough but the dough won’t be perfectly smooth (and that’s okay!)

Shape the dough once again into a rectangle that is 1-inch thick. This is the final shaping. Use your hands or a bench scraper to make the edges tidy.

Use a bench scraper or sharp knife to cut the dough into 8 squares.

Place biscuits on the prepared baking sheet, spacing them 1 to 2 inches apart.

Bake the biscuits for 12-13 minutes or until the tops are a very light golden brown.

Remove the biscuits from the oven and rub the top of each biscuit with a pat of cold butter if desired (I highly recommend not skipping this step!) Serve the biscuits warm.

Store leftover biscuits in an airtight container at room temperature for up to 3 days.