• 5 tbsp. unsalted butter
• 1/2 cup all-purpose flour
• 4 cups warm whole milk
• 1/2 tsp. salt

Melt butter over medium heat. Add the flour and whisk until smooth, about 2 minutes. Gradually add the warm milk, whisking constantly to prevent any lumps from forming. Simmer over medium heat, whisking constantly, until the sauce is thick, smooth, and creamy – about 10 minutes (do not allow to boil). Remove from heat and stir in salt and pepper, pinch of nutmeg.