Why not create a humorous cookbook for your new daughter-in-law, describing your son's eating habits, likes and dislikes over the years? I'm sure you'll be able to pull up some great baby shots with a face full of food, or maybe eating ice cream at the beach, or devouring his birthday cake when he was three. Don't forget to mention his favorite comfort foods like bacon and mayonnaise sandwiches and peanut butter and pickles.
Needless to say, you should also include some of the family favorite menus and dishes. How about mentioning any unusual traditions you have around certain holidays or birthdays?