Heat oven to 350 degrees F. Butter a shallow 2-quart baking dish.
In a large pot of boiling salted water, cook the macaroni until tender but still
firm, about 8 minutes. Drain well.
Meanwhile, in a small heavy saucepan, bring the milk to a simmer over moderate
heat. Remove from the heat and stir in the powdered mustard, Worcestershire sauce,
salt and hot pepper sauce. Set the seasoned milk aside.
Transfer the macaroni to a medium bowl. Add 11/2 tablespoons of the butter and
the egg and mix well. Stir in 3 cups of the Cheddar cheese. Spread the macaroni
evenly in the buttered baking dish. Pour the seasoned milk over the macaroni and
sprinkle with the remaining 1/2 cup grated cheese.
In a small skillet, melt the remaining 2 tablespoons butter over moderate heat.
Stir in the bread crumbs until well-coated. Scatter the buttered crumbs evenly over
the macaroni and sprinkle with the paprika.
Bake for 30 minutes, or until the macaroni is bubbling and lightly colored.
to the broiler and broil about 6 inches from the heat until the bread crumbs are
golden brown, 1 to 2 minutes.