Brown the ground pork sausage in a skillet over medium-high heat, breaking it into small pieces as it cooks, until fully cooked and crumbled (about 8-10 minutes). Reserve the meat grease in the skillet for the gravy—you should have about 1/2 cup. While the sausage cooks, preheat your oven to 350°F and butter a Dutch oven or baking pan generously to prevent sticking.

In a large bowl, whisk together the flour, sugar, salt, baking powder, and cream of tartar. Cut the chilled butter cubes into the flour mixture using a pastry cutter, fork, or your fingertips, working quickly until the mixture resembles coarse breadcrumbs with some pea-sized butter pieces still visible. This creates pockets of steam during baking that make biscuits light and fluffy. I like to chill my mixing bowl beforehand—it keeps the butter cold and makes flakier biscuits.

In a small bowl, beat together the room temperature egg and buttermilk until combined. Pour this mixture into the dry ingredient mixture from Step 2 and stir gently with a fork until the dough just comes together—don't overmix or the biscuits will be tough. Flour your hands and work surface lightly, then turn the dough out and knead it gently 10-15 times until it holds together, being careful not to develop the gluten too much.

Pat the dough from Step 3 out to a thickness of 3/4 to 1 inch on your floured surface. Using a biscuit cutter (or a drinking glass if you don't have one), cut out biscuits and place them in the buttered pan, nestling them close together so they support each other while rising. Bake for 10-15 minutes until the tops are light golden brown. Remove from the oven and brush the hot biscuits with a bit of melted butter for added richness and flavor.

Return the skillet with the reserved meat grease from Step 1 to medium heat. Sprinkle the flour over the grease and stir constantly for about 2 minutes, allowing the mixture to bubble gently—this roux will thicken and darken slightly. Gradually pour in the milk while stirring continuously to avoid lumps, cooking for another 2 minutes until the gravy is smooth and thickened. Stir in the cooked sausage from Step 1 and season generously with salt and black pepper to taste. I always taste as I go and adjust the seasoning right before serving—it makes a real difference.

Split the warm biscuits from Step 4 and arrange them on a serving plate. Pour the hot sausage gravy from Step 5 generously over the biscuits, allowing it to soak into the crumbly layers. Serve immediately while everything is warm and the biscuits are at their fluffiest.