1. Melt 1 1/2 Tbsp. butter in a medium skillet over medium-high heat. Sprinkle 2 Tbsp. flour into melted butter, whisking constantly. Cook, whisking constantly, 30 seconds to 1 minute or until mixture is golden and lumpy.
2. Gradually whisk in 1 cup 1% low-fat milk, and bring to a boil. Cook, whisking constantly, 1 to 2 minutes, or until thickened.
3. Add 1/2 cup freshly shredded Parmesan cheese, 1/4 tsp. each salt and pepper, and a pinch of paprika, whisking until smooth. Remove from heat, and use immediately.
Spicy Cheese Sauce: Prepare Parmesan Cheese Sauce as directed, and whisk in 1 tsp. hot sauce.