Preheat oven to 450°F (232°C) and line a baking sheet with parchment paper.

In a large mixing bowl, whisk together the flour, baking powder, baking soda, and salt.

Incorporate the cold cubed butter into the dry ingredients using a pastry cutter until the mixture resembles coarse meal with pea-sized lumps.

Add the buttermilk and stir gently until a shaggy dough forms, being careful not to overwork.

Turn the dough onto a lightly floured surface and fold it over itself 5 to 6 times to create layers.

Pat the dough to a 1-inch thickness and cut into 8 rounds using a 2.5-inch biscuit cutter.

Arrange biscuits on the baking sheet so they are touching and bake for 12-15 minutes until golden brown.

Divide the breakfast sausage into 8 equal portions and shape into flat patties slightly wider than the biscuit cutter.

Cook the sausage patties in a heavy skillet over medium heat for 4-5 minutes per side until the internal temperature reaches 160°F (71°C).

Split the warm biscuits horizontally and place one sausage patty inside each.