Preheat oven to 375℉.
Brush the partially baked pie shell with mustard. Set aside.
1 9-inch pie shell, 1 tablespoon Dijon mustard
Melt the butter in sauté pan. Cook onions until tender but not brown. You want them to be translucent.
2 tablespoons butter, 1 onion
Cut the asparagus into thirds or fouths, depending on how long the stalks are. Blanche asparagus and immerse in ice bath to stop cooking and preserve color.
Combine the onion and red pepper with the cut asparagus in the sauté pan. Sauté briefly to warm the asparagus and red peppers.
¼ cup marinated roasted red pepper, ½ pound cooked and trimmed asparagus, 1 onion
In a mixing bowl, beat the eggs, milk, salt, and pepper.
4 eggs, 1 cup milk, 1 teaspoon salt, ¼ teaspoon pepper
Pour the egg mixture over the asparagus mixture. Sprinkle with the shredded Cheddar cheese.
1 ½ cups Cheddar Cheese
Bake 35 to 40 minutes or until center is set, covering crust with foil if it starts to brown.
Cool 10 minutes before serving.