Melt butter in a saucepan. Stir in the flour and garlic and cook until blended and bubbly.
Gradually add half-and-half and broth. Cook, stirring, until thickened.
Crumble bleu cheese into the sauce and stir until blended. Taste and add salt if needed.
Add meatballs to sauce and cook as directed on package.
To serve: Spoon meatballs and sauce over the hot mashed potatoes. They are also good over hot cooked rice or noodles. Garnish with chopped parsley.
For appetizers: Use appetizer-sized frozen or homemade meatballs (about the size of large marbles). Prepare as above. Keep warm in a chafing dish. They may be garnished with cooked, crumbled bacon. Have picks nearby for spearing.