Preheat the oven to 350 degrees F. Boil the macaroni until just tender, about 8 to 10 minutes. While the macaroni cooks, lightly butter an 8" x 8" baking dish. Melt the 3 Tbsp. of butter in a medium-sized pot set over medium heat. Mix in flour until well combined and cook, stirring, 1 minute more. Slowly, while whisking, dribble and mix in 1/2 cup of the milk. Cook until the mixture becomes quite thick, and then slowly whisk in the remaining milk. Bring the sauce to a simmer, stirring frequently so it does not scorch on the bottom, and then remove from the heat. Stir in the paprika, salt, pepper and three-quarters of the cheese.
When the macaroni is cooked, drain well and add to the sauce. Spoon the macaroni into the baking dish. Sprinkle with the remaining cheese and breadcrumbs or Parmesan. Bake 15 to 20 minutes, or until the top is light golden and the sauce bubbling.
Note: The milk can be warmed to just below a simmer in the microwave.