Ingredients:
Grated Parmesan cheese
1/4 cup (1/2 stick) butter
5 tablespoons all purpose flour
1 tablespoon Dijon mustard
1 1/2 cups whole milk
6 large egg yolks
1 teaspoon salt
1/4 teaspoon ground black pepper
1 1/4 cups plus 2 tablespoons (packed) coarsely grated Sharp Cheddar cheese (about 6 ounces)
1/4 cup finely grated Parmesan cheese

8 large egg whites

Directions:

1. Position rack in center of oven and preheat to 400°F.
2. Generously butter six 1 1/4-cup soufflé dishes; sprinkle with Parmesan cheese to coat.  Place all six on rimmed baking sheet.
3. Melt butter in heavy large saucepan over medium heat. Add flour and cook without browning until mixture begins to bubble, whisking constantly, about 1 minute
4. Gradually whisk in milk.
5. Cook until smooth, thick and beginning to boil, whisking constantly, about 2 minutes. Remove from heat.
6.  Mix yolks, salt and pepper in small bowl. Add yolk mixture all at once to sauce and whisk quickly to blend.
7. Fold in 1 1/4 cups Cheddar cheese and 1/4 cup Parmesan cheese (cheeses do not need to melt).
8. Using electric mixer, beat whites in large bowl until stiff but not dry. 
9. Fold 1/4 of whites into lukewarm soufflé base to lighten. Fold in remaining whites. 
10. Transfer soufflé mixture to prepared dishes.
11. Place soufflés in oven; reduce heat to 375°F. Bake until puffed, golden and gently set in center, about 25 minutes for small soufflés.  Serve immediately.