Ingredients

BISCUITS

1. 2 cups all-purpose flour
2. 1 tablespoon baking powder
3. 1 tablespoon sugar
4. 3/4 teaspoon salt
5. 1 stick (4 ounces) cold unsalted butter, cut into small pieces
6. 1/2 cup buttermilk
7. 1/4 cup minced red onion
8. 1 large egg, lightly beaten
9. 2 tablespoons finely chopped sun-dried tomatoes (oil-packed)

GRAVY

1. 3/4 pound breakfast sausage, casings discarded
2. 1/2 medium onion, finely chopped
3. 2 tablespoons finely chopped flat-leaf parsley
4. 1 tablespoon finely chopped sage
5. Salt and freshly ground pepper
6. 1 tablespoon olive oil
7. 1/2 pound mushrooms, thinly sliced
8. 1 large leek, white and tender green, thinly sliced
9. 1/3 cup all-purpose flour
10. 2 1/2 cups chicken stock, canned low-sodium broth or milk

Directions

1. make the biscuits: Preheat the oven to 400° and lightly grease a baking sheet. In a large bowl, combine the flour, baking powder, sugar and salt. Using a pastry blender or 2 knives, cut the butter into the flour until it resembles small peas. In a small bowl, combine the buttermilk, onion, egg and sun-dried tomatoes. Stir the buttermilk mixture into the flour just until incorporated. Transfer the dough to a well-floured surface and knead 2 or 3 times.
2. Pat or roll the dough into a 7-inch square, about 3/4 inch thick. Cut the dough into 4 squares and place on the prepared baking sheet. Reduce the oven temperature to 375° and bake on the center rack of the oven for about 25 minutes, or until the biscuits are golden on the bottom and cooked through. 
3. make the gravy: In a medium bowl, combine the sausage with the onion, 1 tablespoon of the parsley, the sage and a generous pinch each of salt and pepper. Scoop walnut-size balls of the sausage mixture onto a large plate. In a large skillet, heat the oil. Add the sausage balls and cook over moderately high heat until browned all over, about 5 minutes. Drain the sausage balls in a strainer set over a bowl. 
4. Pour 1/4 cup of the fat back into the skillet. Add the mushrooms and leek and cook over moderately high heat, stirring occasionally, until softened, about 5 minutes. Stir in the flour and cook, stirring, until lightly golden, about 2 minutes. Gradually stir in the stock and cook over moderately low heat, stirring occasionally, until thickened, about 5 minutes. Return the sausage balls to the skillet and heat through. Season with salt and a generous pinch of pepper and stir in the remaining 1 tablespoon of parsley. 
5. Split the biscuits in half and set the bottoms on 4 dinner plates. Top with the sausage gravy and biscuit tops.

Make Ahead

The biscuits can be frozen for up to 1 week. Reheat in a 350° oven.