Italian Sausage, Tomato and Cheddar Quiche

Heat oven to 425 °F. Fit the pie crust into and up the sides of a pie plate; fold the edge of the dough underneath itself to create a thicker 1/2-in. border that rests on the lip of the plate and crimp as desired. Place on a rimmed baking sheet and bake until lightly golden, 12 to 15 minutes. Remove and reduce oven heat to 375 °F. Meanwhile, heat the oil in a large skillet over medium heat. Add the onion and 1/4 tsp each salt and pepper and cook, stirring occasionally, until soft, 5 to 7 minutes. Add 6 oz Italian sausage (casings removed) to the sautéed onions, and cook, breaking it up with a spoon, until no longer pink, 4 to 5 minutes. Stir in the parsley and 1 cup grape tomatoes (halved). Remove from heat. In a large bowl, whisk together the eggs, sour cream, milk, 1/4 tsp each salt and pepper, and nutmeg, if using. Gently stir in the onion mixture and extra-sharp Cheddar. Pour the egg mixture into the crust. Bake until just set and a knife inserted in the center comes out clean, 35 to 40 minutes. Let rest 5 minutes before serving.