Preheat the oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish with butter or non-stick spray.

Bring a large pot of salted water to a boil. Add the elbow macaroni and cook until just al dente, about 7 minutes. Drain well and return the pasta to the pot.

Pour the melted butter over the warm pasta and toss until the noodles are evenly coated.

In a large mixing bowl, whisk together the evaporated milk, whole milk, eggs, salt, black pepper, and smoked paprika until the mixture is smooth and fully combined.

Spread half of the buttered macaroni in an even layer in the prepared baking dish. Sprinkle half of the sharp and mild cheddar cheeses evenly over the pasta.

Add the remaining macaroni in a second layer. Top with the remaining cheese, reserving a small handful to sprinkle on at the very end.

Slowly pour the milk and egg mixture over the entire dish, ensuring it seeps down into the pasta layers. Sprinkle the reserved cheese on top.

Bake uncovered for 35 to 40 minutes, or until the edges are bubbly and the top is golden brown.

Remove from the oven and let the dish rest for 10 minutes to allow the custard to set. Garnish with chopped fresh parsley before serving.