Preheat oven to 350°F (175°C) and line a muffin tin with blue paper cupcake liners.

In a medium bowl, whisk together the flour, baking powder, and salt.

In a large bowl, cream the softened butter and granulated sugar together until pale and fluffy (about 3 minutes).

Beat in the eggs one at a time, followed by the vanilla extract.

Gradually alternate adding the dry flour mixture and the milk to the batter, mixing until just combined. Do not overmix.

Fill cupcake liners 2/3 full. Bake for 18-22 minutes until a toothpick inserted comes out clean. Cool completely on a wire rack.

Pulse graham crackers in a food processor until they resemble fine beach sand. Place in a shallow bowl.

To make frosting, beat softened butter until smooth. Gradually add powdered sugar, vanilla, salt, and cream. Whip until fluffy.

Spread an even layer of buttercream over each cooled cupcake, then immediately dip the top into the graham cracker crumbs to coat completely.

Decorate by placing a gummy rainbow towel on the sand, resting a Teddy Graham on it, placing a red gummy ring nearby, and inserting a paper umbrella into the cupcake.