In a large mixing bowl, combine the turkey sausage, cooked rice, shredded cheddar cheese, milk, cream of mushroom soup, frozen peas, salt, and black pepper. Mix well.
Transfer the mixture to a baking dish and spread it out evenly.
Bake in the preheated oven for 45 minutes, or until the casserole is bubbly and the top is golden brown.
Let it cool for a few minutes before serving. Enjoy!
Notes:
This casserole can be made ahead of time and refrigerated until ready to bake.