Corny Macaroni & Cheese

This makes enough for 6-8 people but you can easily cut this recipe in half. Fresh corn off the cob is lovely but frozen corn is fine too.

1 lb elbow macaroni
3 cups corn, fresh or frozen/thawed
4 cups milk
8 tablespoons unsalted butter divided (1 stick)
1/2 cup all-purpose flour
6 cups cheddar cheese, grated
1/4 teaspoon white pepper
salt, to taste
1 teaspoon mustard powder
4 medium tomatoes, sliced, drained on a clean dish towel
1 1/2 cups bread crumbs

1. Spray a 4 quart baking dish with cooking spray. 
2. Bring a large pot of water to a boil. Add 2 tablespoons salt and the pasta. Stir and return to a boil. Reduce heat and cook until al dente, about 10 minutes, stirring occasionally. Drain in a colander and add back to the pot along with the corn.
3. While pasta is cooking, melt 4 tablespoons butter in a medium saucepan. Add the flour and stir. Cook for 2 minutes over low heat. Increase heat to medium and whisk in 1 cup milk. Use a flat whisk if you have one. Whisk in the remaining milk and stir occasionally. Add the white pepper, mustard powder, and about ½ teaspoon salt. (Taste it later after you put the cheese in to make sure it’s salty enough.) When the mixture thickens, stir in the grated cheese, 1 cup at a time with a wooden spoon, letting each cup melt before adding in the next cup. Taste and add more salt if it needs it. Remove from heat. Pour cheese mixture into pasta pot and stir everything together. Pour into prepared pan.
4. Melt the remaining butter in a small saucepan and stir in the breadcrumbs.
5. Heat oven to 350°F. Lay the tomato slices over the macaroni and sprinkle with the buttered breadcrumbs. Bake for 30 minutes until the bread crumbs are golden.