3 slices white sandwich bread for fresh bread crumbs. (Process was torn slices of bread in a blender with the butter to make the bread crumb topping)
2 tablespoons unsalted butter (cold), cut into 6 pieces
Pasta and Cheese sauce
8 ounces elbow macaroni
3 tablespoons unsalted butter
1 small onion (finely chopped)
3 tablespoons all-purpose flour
8 ounces smoked sausage (cut lengthwise into quarters and then cut into 1/2 inch slices)
3/4 teaspoon powdered mustard
2 ½ cups milk
1 cup shredded Monterey Jack cheese
1 cup shredded sharp cheddar cheese
2 teaspoons Honey Dijon mustard
¼ teaspoon table salt or to taste
Cook pasta according to package directions; drain and set aside.
Preheat oven to 400F.
Melt butter in a large kettle over medium-high heat, and then add the onion and dry mustard. Cook until onion starts to brown; stirring as needed.
Gradually mix in the milk and bring the mixture to a boil, stirring constantly until mixture starts to thicken. Remove the mixture from the heat and stir in the cheeses, ¼ teaspoon salt, and Dijon mustard. Continue mixing until cheese is melted. Stir in the macaroni, and then fold in the smoked sausage.
Lightly spray an 8 x 8 casserole dish with cooking spray, spoon in the macaroni and cheese, and then top with the bread crumb-butter mixture.
Bake for 15 to 20 minutes until casserole is heated through and bread crumbs are golden brown.