This is a recipe I got from my mother-in-law and I tweaked it to make it gluten-free. It's very yummy and definitely much better than the gluten-free macaroni and cheese you can buy in the store.
Macaroni and Cheese
2 cups uncooked rice macaroni (we have used elbows or pasta shapes - both from Tinkyada)
1 serving of the Gluten-free condensed mushroom cream soup
1/2 cup milk
1 tsp. Gluten-free prepared yellow mustard
3 cups shredded cheddar cheese
salt & pepper to taste
1. Cook macaroni to desired tenderness, drain.
2. Mix together: soup, milk, mustard, salt, and pepper
3. Pour soup mixture over macaroni and mix.
4. Stir in 2 cups of the shredded cheddar cheese.
5. Bake in a casserole dish (I use 11x7) at 425 degrees F until hot and bubbly.
6. Just before removing from oven, sprinkle the last cup of cheddar cheese on top and return to the oven just until melted.