Holiday Sausage and Sweet Potato Breakfast Casserole

Preheat the oven to 400 degrees F (200 degrees C). Lightly grease a 9x13-inch baking dish.

Combine sweet potatoes with 2 tablespoons olive oil, 1 teaspoon kosher salt, garlic powder, and 1/2 teaspoon black pepper on a large baking sheet in a single, even layer; toss to coat well.

Bake in the preheated oven until slightly browned, about 30 minutes.

Meanwhile, heat remaining 1 tablespoon olive oil in a large skillet over medium-high heat. Add onion and red pepper; cook and stir until translucent, 2 to 3 minutes. Add garlic and stir for 1 more minute. Transfer mixture to a medium mixing bowl.

Heat the same skillet over medium-high heat. Add sausage; cook and break apart with a spatula until cooked through, 5 to 7 minutes. Drain sausage and add to the bowl with the veggie mixture. Add spinach, mozzarella cheese, and rosemary to the mixture.

Gently whisk eggs, milk, and remaining kosher salt and black pepper together in a bowl until well combined. Pour over the sausage and veggie mixture and gently toss to combine.

Place roasted potatoes in the bottom of the prepared baking dish. Pour the veggie and sausage mixture evenly over top.

Bake, uncovered, in the preheated oven until eggs are set in the center, about 50 minutes. If the egg mixture starts to brown, put a loose sheet of aluminum foil over the baking dish to cover it.