Bolognese sauce is typically made of a combination of the following ingredients: A mix of ground beef and ground pork is commonly used to create the base of the sauce, Aromatic vegetables such as finely chopped onions, carrots, and celery are sautéed in olive oil. Canned tomatoes, tomato paste, or fresh tomatoes, a small amount of red sometimes added to enhance the depth of flavor and lend a subtle undertone to the sauce. Salt, pepper, bay leaves, thyme, and nutmeg are commonly used to season the sauce and add aromatic complexity.