Preheat oven to 375° F. Grease or spray a 2-quart shallow baking dish. Cook macaroni according to package directions. Drain and rinse with cold water. In the same pot, melt butter over low heat. Pour about 1 tablespoon into a small bowl; set aside. Stir the flour into the remaining butter in the pot. Cook, stirring constantly, until bubbly, about 1 minute. Gradually stir in milk. Add salt, pepper and cayenne. Bring sauce to a simmer for 3 minutes, stirring frequently. Add Cheddar cheese cubes and stir until partially melted. Remove pot from heat and add macaroni and 2 tablespoons Parmesan or Romano cheese; stir until blended. Pour into prepared baking dish. Crumble bread to make coarse crumbs. Add crumbs and remaining Parmesan or Romano cheese to melted butter in bowl. Toss to combine. Sprinkle on macaroni mixture. Bake 25 to 30 minutes, or until crumbs are browned and macaroni is bubbly at edges.
*Cheddar cheese cubes in this recipe means there are rich pockets of melted cheese throughout!