Melt butter in a pot. Add flour and cook, stirring frequently, for 2 to 3 minutes. Slowly whisk in milk and cook, whisking vigorously to prevent lumps, until milk is hot, about 1 minute. Add grated cheese and stir until melted. Add salt, pepper and nutmeg. Stir to mix well. Taste and adjust seasoning.
YIELD: 2 cups
PREP TIME: 5 min I COOK TIME: 15 min I TOTAL TIME: 20 min