MELT 2 tablespoons butter in a heavy bottom roasting pan. Add pancetta, beef, onions, carrots, celery, and garlic. Brown on medium-high heat while stirring for about 10 minutes. Add mushrooms and cook 5 minutes more, then season with black pepper. Add white wine, chicken broth and tomatoes.
SIMMER sauce on medium heat and cook about 2 hours, or until meat is tender. Add 1/4 cup of chilled butter while stirring sauce until butter is completely melted. Taste and adjust seasoning with salt and pepper.
ADD cooked, drained ravioli to sauce and stir to coat pasta. Place sauced ravioli on serving plate. Top with grated Parmesan and parsley.
Substitute reconstituted dried porcini mushrooms for domestic mushrooms. Substitute thick bacon for pancetta. Add roasted red peppers to sauce. Add capers or black olives to sauce.