Whisk together the flour, baking powder and salt in a small bowl and set aside. In a large bowl, combine the butter, sugar, honey, egg and vanilla extract. Add the buttermilk and mix until combined. Add the dry ingredients and mix until just combined – make sure not to overmix.
Spoon the batter into a piping bag, then pipe the batter into a greased doughnut pan and bake at 400F for 7 minutes. Cool for 1 minute in the pan, then flip the pan over to remove the doughnuts and cool completely on a wire rack.
Pour the blue, pink and purple candy melts into a shell-shaped chocolate mold. Place the mold in the freezer until the candy melts have set, about 20 minutes.
Make the glaze: Whisk together the whipping cream and the confectioner’s sugar and whisk until fully combined. Divide the glaze into 3 bowls and dye it pale blue, pale pink and pale purple. Dollop each colour into a larger bowl.
Dunk the doughnuts into the glaze. The marble pattern will continue to change as you dunk more doughnuts. Place them on a wire rack. Sprinkle a tiny bit of brown sugar on top to look like sand and decorate with gum ball “pearls” and silver star sprinkles. Top with the chocolate shells. Enjoy!