Prep the proteins and vegetables: Brown the sausage in a skillet over medium heat, breaking it into small crumbles as it cooks (about 5-7 minutes). Set aside. Dice your jalapeños, sweet peppers, onion, and tomatoes. Pat the tomatoes dry with paper towels to prevent excess moisture in the quiche.
Make the custard base: In a large bowl, whisk together the eggs and cream until well combined. Season with salt, pepper, and optional cumin or garlic powder. Set aside.
Prepare the baking dish: Butter a 9-inch pie dish or 8x8 baking dish generously, making sure to coat the bottom and sides well.
Layer the filling: Spread the cooked sausage evenly on the bottom of the dish. Layer half of the diced peppers, onion, and tomatoes over the sausage. Sprinkle half of the cheese blend (cheddar and mozzarella mixed together) over the vegetables.
Add the custard: Slowly pour the egg mixture over the layered ingredients, making sure it distributes evenly throughout.
Top it off: Add the remaining peppers, onion, and tomatoes, then top with the remaining cheese blend. Finish with a sprinkle of Parmesan cheese across the top for a golden, crispy finish.
Bake: Place in a preheated 350°F oven and bake for 35-45 minutes, until the center is just set. The quiche should jiggle slightly when you gently shake the pan—this means it's perfectly creamy inside. A knife inserted near the center should come out mostly clean.
Rest and serve: Remove from the oven and let rest for 10 minutes before slicing. This resting period allows the quiche to set up and hold together beautifully.