Bring a large pot of salted water to a boil. Add macaroni and cook until just al dente. Drain and set aside. Avoid overcooking, as the pasta will continue to cook in the oven.

Heat olive oil in a skillet over medium heat. Add minced garlic and cook for about 30 seconds until fragrant. Add shrimp and crab (or fish) and cook for 3–4 minutes until just done. Season lightly with salt and pepper, then set aside.

In a saucepan, melt butter over medium heat. Add flour and whisk continuously for 1–2 minutes to create a smooth paste. This step removes the raw flour taste.

Slowly pour in the milk while whisking to avoid lumps. Continue cooking until the mixture thickens into a smooth, creamy sauce.

Reduce heat and stir in cheddar, mozzarella, and Parmesan. Mix until fully melted and smooth. Add paprika, salt, and black pepper.

In a large bowl, mix the cooked pasta, seafood, and cheese sauce. Stir gently until everything is evenly coated.

Transfer the mixture into a greased baking dish. Combine breadcrumbs with melted butter and sprinkle evenly over the top.

Bake at 180°C (350°F) for 20–25 minutes until the top is golden and slightly crispy.

Let the dish sit for 5–10 minutes before serving. This helps the sauce settle and makes it easier to serve.