Add butter and cheese mix from box to cooked macaroni. Then add 1/3 can of milk. Stir well. Whip 8 eggs and remaining milk together, and then stir into Mac-N-Cheese. Mix both kinds of cheese together add to mixture-- save some cheese to top with. Pepper top.
Mix and cook in a Dutch oven at 350°F for 45 minutes to 1 hour.