Hi! I would double check the pre-school treats policy first. At my kids' preschool, I couldn't bring in home-made treats...they had to be store bought so the ingredients were listed. There were just too many allergies in the school to take any chances. That being said, for a treat, your could make cream cheese and strawberry jam sandwiches, then get cookie cutters in a shape your son likes and use them to cut out the sandwiches. It's a sweet treat, but much more healthy, especially if you use whole wheat bread. Or rice krispies treats are always good, especially if you put in a touch of food coloring to make them fun colors (mix it into the melted butter/marshmallow part). Have fun!!