Start by bringing a large pot of salted water (with 1 Tbsp salt and Old Bay seasoning) to a boil. Once boiling, add the shrimp and cook for about 2-3 minutes, or until they turn pink and opaque. Drain and set aside.
In a mixing bowl, combine the mayonnaise, garlic powder, and ground black pepper. Stir well until the mixture is smooth and evenly blended.
Add the cooked shrimp to the mayonnaise mixture. Gently fold the shrimp into the sauce until they are well coated.
Preheat your oven to 350°F (175°C). Grease a 2-quart baking dish with butter to ensure the casserole doesn’t stick.
Pour the shrimp mixture into the prepared baking dish. Spread it out evenly, then sprinkle the shredded mozzarella and cheddar cheese on top.
In a small bowl, mix the panko bread crumbs with a little melted butter (about 1 Tbsp) to help them brown nicely. Sprinkle this mixture evenly over the cheese layer.
Place the baking dish in the preheated oven and bake for 25-30 minutes, or until the cheese is bubbly and the top is golden brown.
Once baked, remove the casserole from the oven and let it cool for a few minutes before serving. This Shrimp Casserole Recipe is delicious on its own or served with a side salad or crusty bread.
