Cook macaroni per package directions until tender. Drain.
In a large bowl, combine flour, salt, pepper and 1/2 Tbsp smoked paprika and set aside.
Coat 3-quart casserole dish with cooking spray. Place half of the cooked and drained macaroni in dish. Sprinkle half of the flour mixture over top, then top with half of butter cubes. Sprinkle 1 1/2 cups cheese over top. Repeat layers with remaining ingredients, ending with cheese.
Pour milk over all. Sprinkle the remaining 1/2 Tbsp over the top. Cover dish with foil and bake for 35 min. Remove foil and bake for an additional 10 min, until bubbly. Let the dish sit for 5 min before serving.