Preheat oven to 350° F and grease a large baking dish with oil. 

In a large pot over medium heat, heat oil. Add onion and cook, stirring, until soft. 5 minutes. Add garlic and cook until fragrant, 1 minute. 

Add ground beef and cook. breaking up meat with a wooden spoon, until no longer pink, about 6 minutes. Drain fat. 

Return beef mixture to skillet over medium heat and pour in wine, using a wooden spoon to scrape up any browned bits from bottom of pan. Cook until reduced by about half, then add tomato paste, crushed tomatoes, and oregano and season with salt and pepper. Bring mixture to a simmer and cook until slightly reduced, about 10 minutes. 

Put tortellini in prepared baking dish. Pour over meat sauce and stir until coated. Top with mozzarella and Parmesan, then cover dish with foil. 

Bake until cheese has melted and pasta is cooked through, 25 minutes. 

Garnish with basil before serving.