Line the base and sides of a loaf tin with baking paper.
Place the marshmallows and butter in a large microwave-safe bowl and microwave for 90 seconds. If not melted, cook another 30 seconds. Make sure you use a very large bowl as the marshmallows will expand considerably.
Give it a stir and then mix in 1 tsp essence and a few drops pink colouring then fold through the puffed rice.
Spread the mixture into the tin and press the top down with a spatula. Refrigerate for at least 2 hours.
Make the icing according to the instructions on the packet and add remaining essence and a few drops food colouring. Spread the icing over the rice crispie then decorate with soft sugar pearls and cut into squares.