Using the leftover oil in the skillet from cooking the meatballs, add the onion and garlic to the oil and cook over medium high heat for a couple minutes until fragrant.
Add the frozen gnocchi, toss to combine, and cook for about 7 minutes until the gnocchi is cooked and has some color on the sides.
Pour in the wine to deglaze the pan. Add the spinach here too, mix to combine and let the spinach wilt a little.
Pour in the spaghetti sauce, and mix all of the skillet ingredients into the sauce.
Put the meatballs back into the skillet gently. Cover the skillet with a lid, and cook over low to medium heat for 10 minutes until the meatballs are cooked through. You want the skillet sauce to be at a low simmer.
Top each bowl with parmigiano Reggiano if you wish!