Preheat oven to 425 degrees F. Lightly oil a 9 x 13 baking dish or coat with nonstick spray.
Heat olive oil in a large skillet over medium high heat. Add ground beef and onion, and cook until beef has browned, about 3-5 minutes, making sure to crumble the beef as it cooks; drain excess fat.
Stir in garlic until fragrant, about 1 minute.
Stir in wine, scraping any browned bits from the bottom of the pot.
Stir in marinara sauce. Bring to a boil; reduce heat and simmer until flavors have blended, about 5 minutes. Stir in gnocchi, Parmesan and parsley until well combined, about 1-2 minutes.
Spread gnocchi mixture into the prepared baking dish; top with mozzarella. Place into oven and bake until bubbly, about 20-25 minutes. Let stand 5 minutes.
Serve immediately, garnished with basil, if desired.