Step 1

Heat broiler. Cook pasta per package directions, drain and return to pot.

Step 2

Meanwhile, chop 1 cup spinach. In a large bowl, whisk together the egg, 2 tablespoons of water, and 1/2 teaspoon each of salt and pepper. Stir in the garlic and parsley, then the bread crumbs and Parmesan. Let sit for 2 minutes. Add the beef, sausage, and chopped spinach and mix to combine.

Step 3

Form the meat mixture into 1 1/2-inch balls (about 20 total) and place on rimmed baking sheet. Broil until cooked through, 6 to 8 minutes.

Step 4

Toss the pasta with the marinara sauce. Fold in 1 cup mozzarella, 1/4 cup of ricotta, then meatballs and remaining 2 cups spinach. Transfer to a 3-quart baking dish. Sprinkle with the remaining 1/2 cup mozzarella and dollop with the remaining 1/4 cup ricotta. Broil until golden brown, 2 to 3 minutes.