01 - Set oven temperature to 375°F and allow to preheat.
02 - Boil elbow macaroni in salted water following package directions until al dente. Drain thoroughly and set aside.
03 - Steam or blanch broccoli florets for 2 to 3 minutes until just tender but bright green. Drain and reserve.
04 - In a 10 to 12-inch ovenproof skillet, melt butter over medium heat. Add diced onion and sauté for 3 to 4 minutes until softened.
05 - In a large mixing bowl, whisk together eggs, whole milk, heavy cream, salt, ground black pepper, and smoked paprika.
06 - Add drained macaroni, shredded cheddar cheese, grated Parmesan, and steamed broccoli to the egg mixture. Fold gently to combine evenly.
07 - Pour mixture into the skillet over the sautéed onion and stir briefly to distribute ingredients.
08 - Cook over medium heat for 4 to 5 minutes, running a spatula around the edge until edges are set but center is still slightly loose.
09 - Transfer skillet to preheated oven. Bake for 15 to 18 minutes until fully set and lightly golden on top.
10 - Allow frittata to cool for several minutes, then slice and serve warm.