Tuna Rice Casserole

I discovered this as I was attempting to make a hearty dinner from just the items I had on hand. Simple, easy, and yummy!

Tuna Rice Casserole

4 cups cooked rice
1 tbsp oil
1 cup onion, diced
1.5 cups frozen peas
1 can tuna, drained
1 can mushroom soup
1 cup milk (omit if not using condensed soup)
1/2 tsp ground mustard
1/2 tsp pepper
1/4 tsp cayanne
1.5 cups shredded cheddar cheese

Preheat oven to 400. Over medium heat, sautee onion in oil. Add peas and cook till peas and onions are tender. Meanwhile in large bowl, combine tuna, mushroom soup, milk, mustard, pepper, cayenne and cheese. Stir well. Mix in rice and peas and onions. Pour all into 2 quart casserole dish. Top with additional shredded cheese if desired. Bake for 20 minutes or until heated through.