Preheat the oven (skip if using air fryer) to 425 degrees F (218 °C). Line a baking sheet with parchment paper.

In a medium bowl, mix the flour, baking powder, sugar, and salt with a fork.

Add the cold, butter pieces to the dry ingredients and cut into the flour mixture with a pastry blender (or even your fingers) until pea sized pieces form.

Add the 2 tablespoons of milk and stir with a fork to combine until everything is moistened.

Pour the dough out onto a floured surface and press together. Fold the dough over on top of itself several times, to form layers. Then press into a circle that is about ¾ inch thick.

Place on the lined baking sheet and pop in the fridge until the oven finishes preheating (it's important to keep them cold until baking).

Bake in the preheated oven for 13-15 minutes. The biscuit is done when it are golden brown and have crisp edges.

Alternatively, you can air fry the biscuit at 390 degrees F (199 °C). for 9-11 minutes until it is golden brown with crisp edges.

While the biscuit bakes, make the gravy. Heat a small skillet over medium heat. Add the sausage and brown while crumbling until fully cooked. This only takes a minute or two since it's such a small amount of meat.

Sprinkle the flour over the sausage, stir to combine and cook for about 30 seconds. Then add the milk, stir constantly, until it thickens and is bubbly. This only takes a few minutes. Stir the seasoning into the gravy.

Cut the biscuit in half and spoon the sausage gravy over the top. Garnish with sliced chives, if using, and enjoy!