I used this template as our Mother's Day gift last year, and I intend to use it again this year. I purchase several different sundae toppings (chocolate sprinkles, rainbow sprinkles, marshmallows, nuts, chocolate chips, M&Ms, coconut shavings, gummy bears, candy bar pieces, etc), and snack sized sealable bags. We layer the bags in the empty space (see preview picture for example of completed project), and the kids sign their masterpiece and take it home to Mom!
Disclaimer: Ice Cream not included :)
Disclaimer #2: You will have to do some trimming (or have the kids do it) around the outside in order to get the look of the preview picture.