Hi Kate,
Thank you so much for visiting the Disney Parks Moms Panel with your question.
Beaches & Cream Soda Shop is one of my family's favorite hidden gem restaurants at Walt Disney World. The casual beach diner feeling and the positively scrumptious ice cream are fantastic!
Generally speaking, there are not snack items available for using snack credits at table service restaurants. Since Beaches & Cream Soda Shop is a table service restaurant, chances are you will not find menu items listed as snacks. There is a bit of a unique situation with this restaurant because there is the to-go window attached, where guests can walk up and order food to go. At the to go window, there are items listed as snacks. Thus, it seems to be that if you want to be guaranteed that you can use your snack credits, you could cancel your reservation and just head to the to-go window. Also, remember that snack credits are typically used for small snacks, so something like an ice cream cone. If you want the gigantic and delicious Kitchen Sink Sundae, you will not be able to use a snack credit, and it that situation you could keep your reservation to sit down and enjoy the amazing sundae using a payment method other than your Disney Dining Plan snack credits.
I hope that these thoughts are helpful for you, Kate. Have a wonderful time planning your magical vacation, and please do not hesitate to ask if you have any further questions.