Heat the olive oil in a large skillet or saucepan over medium heat. Add the carrot, celery, and onion, cooking until softened, about 5 minutes.

Add the ground beef and ground pork to the pan, breaking them up with a wooden spoon. Cook until browned and no pink remains.

Pour in the red wine, stirring to deglaze the pan, and simmer for 2-3 minutes until the wine reduces slightly.

Add the tomato paste and stir well to combine. Then pour in the tomato sauce, mixing thoroughly.

Stir in the milk, bay leaves, salt, and pepper. Lower the heat to a gentle simmer.

Cover the pan partially and cook over low heat for 1 1/2 to 2 hours, stirring occasionally to prevent sticking. Adjust seasoning if needed.

Meanwhile, cook the spaghetti according to the package instructions. Drain and set aside.

Remove the bay leaves from the sauce and discard. Serve the Bolognese sauce over the cooked spaghetti, and enjoy.