In a large mixing bowl, combine the cooked rice, seafood mix, milk, shredded cheddar cheese, cream of mushroom soup, frozen peas, salt, and black pepper. Mix well.
Transfer the mixture to a greased casserole dish.
Bake in the preheated oven for 40 minutes, or until the top is golden and bubbly.
Let it cool for a few minutes before serving.
Notes:
You can use any seafood you like. Adjust the seasoning to your taste.