Use a little butter to grease a 20 x 20cm/8" x 8" baking tin, then line with parchment paper.
Add 150g butter and tear in 6 Mars bars to a large heat-proof mixing bowl and place over a pan of barely simmering water. Use a whisk to help it combine as it melts.
Pour over the 120g rice krispies into the mixing bowl and mix until all the ingredients are evenly combined.
Press evenly into the prepared baking tin and set aside.
Melt the milk chocolate in the microwave or over a pan of barely simmering water.
Spread the melted chocolate over the rice krispie mixture and leave to set in a cool place.
Once set slice into squares and serve!
Notes
Chewy, chocolatey, caramely and crispy all in one bite – do I even need to go on? A simple way to make chocolate treats – definitely NOT an every day indulgence!