INGREDIENTS

1 pound elbow macaroni, cooked shy of all dente in boiling, salted water
3 tablespoons unsalted butter
3 tablespoons all purpose flour
3 cups milk
1 teaspoon Dijon mustard
1/3 pound shredded sharp white cheddar
1/3 pound shredded Gruyère (4 cups of cheese total)
1 cup half and half
1 cup fresh baguette crumbs (optional)
1 additional tablespoon butter, room temperature (optional)

PROCEDURE

1. Preheat the oven to 375 degrees F.
2. In a saucepot, melt the 3 tablespoons of butter, and stir in the flour. Cook on medium-low heat until the roux bubbles and begins to smell like baking cookies.
3. Slowly whisk in the cold milk, avoiding any lumps. Cook on medium to medium-high heat until the sauce has thickened enough that if you dip a spoon it in and run your finger through the sauce on the back of the spoon, the sauce stays separated and your finger leaves a stripe.
4. Add in the cheese and Dijon mustard. Pour the cheese sauce over the macaroni, and thoroughly toss. Season with salt and pepper to taste.
5. Divide the mixture between 6 buttered gratin dishes. Pour the half and half over the pasta mixture, dividing it between the 6 gratin dishes.
6. If you want a breadcrumb topping, use your fingers to work together 1 cup of fresh crumbs and 1 tablespoon of soft butter. Scatter over the top of the gratin dishes.
7. Place the gratin dishes on a baking tray, and bake for 40 to 45 minutes, until bubbly and golden brown.