Preheat the oven to 375°F (190°C).
If using a store-bought pie crust, place it in the pie dish and pierce the bottom with a fork to prevent bubbling. If using homemade, roll it out and place it in the dish, trimming any excess.
In a skillet over medium heat, add the chopped onion and bell pepper. Sauté until soft, about 5 minutes.
Add the crumbled cooked sausage to the skillet and cook for an additional 2-3 minutes, ensuring it is heated through. Remove from heat and let cool slightly.
In a mixing bowl, whisk together the eggs, milk, salt, black pepper, garlic powder, and paprika until well combined.
Spread the sausage mixture evenly over the pie crust, then sprinkle the shredded cheddar cheese on top.
Pour the egg mixture over the sausage and cheese, ensuring it fills to just below the top of the crust.
Bake in the preheated oven for 35-40 minutes, or until the quiche is set in the center and lightly golden on top. A toothpick inserted should come out clean.
Allow the quiche to cool for at least 10 minutes before slicing and serving.