Preheat oven to 350 degrees F (175 degrees C). Grease a 2-quart casserole with butter.
Dissolve salt in a large pot of water. Bring to a boil and cook macaroni, stirring often, until pasta is tender but still slightly firm to the bite, about 8 minutes. Rinse macaroni under cool water, drain, and transfer to a bowl. Stir 1/4 cup softened butter into macaroni and toss a few times to melt butter and coat macaroni.
Beat eggs in a bowl; whisk evaporated and condensed milks into eggs.
Spread a layer of macaroni into the bottom of the prepared casserole; sprinkle with a layer of Cheddar cheese. Continue layering macaroni and cheese, ending with a layer of cheese on top. Pour egg-milk mixture over the layers. Use a fork to gently dig into the layers, assuring that the egg-milk mixture flows into all the layers. Sprinkle with paprika.
Melt 1/4 cup butter in a small skillet over medium heat; cook bread crumbs in the hot butter, stirring constantly, until fragrant and golden, 2 to 3 minutes. Sprinkle crumb topping over casserole.
Bake in the preheated oven until casserole is browned and bubbling, about 45 minutes.