Melt butter with oil in a large saucepan over medium heat. When butter foams, add onion, carrot, celery and pancetta. Sauté until lightly browned.
Add veal. Cook, stirring, until meat is no longer pink. Season with salt and pepper. Increase heat to high and stir in wine. Cook until wine has evaporated.
Press tomatoes through a food mill or sieve to remove seeds. Stir tomato pulp into veal mixture. Cover and reduce heat. Simmer 1 to 1 ½ hours or until sauce reaches a medium-thick consistency; stir occasionally during cooking.
Add milk and cook 5 minutes longer, stirring occasionally.