Heat a large cast-iron skillet over medium-high heat. Add the sausage, break it up with a wooden spoon, and cook, stirring occasionally, until well browned and cooked through, about 7 minutes.

Using a slotted spoon, transfer the sausage to a bowl, leaving the rendered fat in the skillet. Whisk the flour into the fat and cook, stirring, for about 1 minute. While whisking, pour the milk into the skillet and bring the gravy to a boil. Lower the heat and simmer gently for 2 minutes. Stir in the sausage and season with pepper. Split the biscuits in half and divide them among plates. Top each biscuit with some of the gravy and serve immediately.

Biscuits:
2 cups all-purpose flour (about 8 ounces), plus more for dusting
1 tablespoon baking powder
1 teaspoon sugar
1 teaspoon fine salt
7 tablespoons cold unsalted butter, sliced
3/4 cup milk

Biscuit Glaze:

1 tablespoon heavy cream
1 tablespoon unsalted butter, melted

To make the biscuits:

Place a rack in the center of the oven and preheat to 450 degrees F. Line a baking sheet with two layers of parchment paper. Set aside.

In a large bowl, whisk together the flour, baking powder, sugar, and salt. Rub 2 tablespoons of the butter into the flour with your fingertips until completely absorbed. Work the remaining butter into the flour until it is in even pieces about the size of a pea. Gently stir the milk into the flour mixture to make a loose dough.

Lightly dust a clean work surface with flour and turn the dough out onto it. Pat the dough into a 1/2-inch thick rectangle. Fold the dough in thirds like a business letter. (For a flakier biscuit repeat the folding a second time.) Pat the dough into a 5 by 8-inch rectangle about 3/4-inch thick. Use a 2- to 3-inch round cutter to make 6 biscuits, and transfer them to the prepared baking sheet. Press together the scraps of dough and cut 2 more biscuits.

To make the biscuit glaze:

Mix the cream and melted butter together in a small bowl. Lightly brush the tops of the biscuits with the glaze. Bake until lightly browned, about 15 minutes. Cool on a rack for 5 minutes before serving.