Chop Mars Bars and melt in saucepan with the butter and maple syrup on low heat. Stir continuously until melted, making sure to scrape the bottom of the saucepan regularly.

Measure the rice bubbles into a seperate, heat proof bowl.

Pour chocolate mixture over the Rice Bubbles and combine.

Press into a lined 20x20 inch cake tin. Make sure to get it into the corners.

Melt the cooking chocolate. Be careful to stir it regularly so it doesn't burn. You can melt in the microwave or in a heat proof bowl over a saucepan with some water in the bottom. Never heat directly over heating element.

Pour melted chocolate over the top of the mixture in the tin.

Refrigerate for three hours, or until set.

Slice into 16 squares, using a hot, dry knife and then refrigerate.