If you are using canned peas and carrots, drain them and rinse with fresh water. Put 2 tbs. of the butter in a pan, add the vegs.; saute for 2 or 3 min. Add salt & pepper. Put the remaining butter into another frying pan, and heat. Beat the eggs with the milk (or water); pour into the pan and let cook. As soon as the omelet is set, top with the vegs. and cheese. Fold in half, and serve immediately.