1 pound cavatappi pasta, or any shape you like
Salt and freshly ground black pepper
3 tablespoons butter, plus 1 tablespoon, divided
3 tablespoons flour
2 cups chicken stock
1 cup milk
1/4 cup spicy deli mustard
3 cups New York aged sharp cheddar (12 ounces), grated
1/2 pound deli pastrami, roughly chopped
6 slices rye toast, crumbled
Pre-heat broiler to high or oven to 400°F.
Place a large pot of water over high heat and bring it up to a boil to cook the pasta. Once at a boil, add some salt and the pasta and cook until al dente, according to package directions.
While the pasta is cooking, heat a medium size skillet over medium heat and add the butter. When the butter melts, add flour and cook about a minute. Whisk in stock, milk and spicy mustard and bring up to a bubble. Stir in the cheese in a figure-eight motion, reserving enough to sprinkle on the top of the casserole, until it's all melted. Fold in the pastrami and season with salt and pepper to taste.
When the pasta is done, drain it well and combine with sauce. Pour into a baking dish and top with reserved cheese and crumbled rye toast. Dot the top of the casserole with butter and place in oven until cheese is brown and bubbling.