You may also freeze baked cookies. Iced cupcakes freeze well and thaw relatively quickly. Color, cupcakes and chocolate . I make large vanilla or chocolate sheet cakes in jellyroll pans, ice them and sell them in squares. Brownies are a must.
Good displays go a long way .
See restaurant supply stores or any gourmet kitchen supply shops. The jars are relatively inexpensive and they perform double duty as flour and sugar canisters in the off season. Large cookies, even if they are priced a little higher, go first. Don't forget the teachers . Bake sales appeal to all ages.