Slice the zucchini and summer squash into 1-inch rounds. In a medium pot, bring to boil about an inch of water. Add the squash. Cover the pot and cook until fork tender (about 7-8 minutes) (check to make sure water has not evaporated, and add more water, if necessary). When it is done, pour the squash into a colander and drain it well. Return the squash to the pot. Add butter and milk, stirring and mashing to break up the squash into small pieces. Add the shredded cheese (or strips of American Cheese) - the secret ingredient! - and mix until completely incorporated. Add salt and pepper to taste. Serve hot.