Preheat oven to 400ºF.
In a large skillet over medium-high heat, sauté onions, ground meat, salt and pepper; breaking up into a crumble with back of spoon, until cooked through.
Add garlic and cook 1 minute more. Add tomatoes, tomato paste, oregano, basil, parsley and sugar. Bring up to a boil, reduce heat to medium-low and simmer for 10 minutes.
Add spinach and stir in to allow spinach to wilt into sauce. Add gnocchi and toss to coat.
Transfer to a 9” x 13” baking pan, top with cheese and bake for 15 minutes.