Melt butter in heavy, medium-size saucepan over medium heat. Add asparagus and garlic; sauté about 5 minutes. Gradually blend in flour; cook, stirring, 3 to 5 minutes.
Reduce heat to medium-low. Gradually stir in 1 cup milk and cheese; cook, stirring, 5 minutes or until cheese is melted and smooth.
Stir in remaining milk, mustard, salt, pepper and nutmeg. Gently heat, stirring, until soup is hot.
To serve, remove garlic. Garnish with shredded cheese if you wish.