Heat the olive oil in a large skillet over medium heat.
Add the onion, garlic, celery, and carrot. Sauté for about 5 minutes until softened.
Stir in the ground beef, breaking it up with a spoon. Cook until browned.
Pour in the milk and simmer until absorbed, about 3 minutes.
Add the white wine and let it cook down for another 3-4 minutes.
Stir in the crushed tomatoes, oregano, chili flakes, salt, and pepper.
Lower the heat and let the sauce simmer gently for 30-40 minutes, stirring occasionally.
Meanwhile, cook the spaghetti according to package instructions until al dente.
Drain the pasta and serve with the Bolognese sauce, topped with fresh basil and Parmesan.