Line a 12x10” baking tray with non-stick baking parchment.
Melt the butter in a large saucepan over a low heat. Add the marshmallows and stir until melted together.
Remove from the heat. Gently stir in the rice crispies, followed by the Jumble Bee tropical pieces.
Press into the baking tray using the back of a lightly greased spoon.
Allow to cool before cutting into squares, or use cookie cutters to make any shape you choose.