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Two chocolate-topped crispy rice treats are stacked on a wooden surface, with more treats in the background and some green leaves out of focus.

Mars Bar Cake (Chocolate Tray Bake)

Lauren
This Mars Bar Cake is a nostalgic throwback tray bake treat from primary school for me. And it's got to be one of my kids favourite things to make (and more importantly, eat!) too.
5 from 4 votes
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Prep Time 5 minutes
Cook Time 10 minutes
Refrigeration 2 hours
Total Time 2 hours 15 minutes
Course Dessert
Cuisine British
Servings 12
Calories 493 kcal

Ingredients
 
 

  • 380 g Mars Bars chopped
  • 100 g salted butter
  • 2 tablespoon golden syrup or maple syrup
  • 200 g rice krispies
  • 200 g carnation caramel optional layer
  • 480 g chocolate

Instructions
 

  • Melt 100 g salted butter with 2 tablespoon golden syrup in a Bain-Marie (or microwave - see note below) on a low heat then add 380 g Mars Bars (chopped) and stir occasionally until fully melted 
  • Pour 200 g rice krispies into the melted mixture, mix to combine and then pour into a grease proof paper lined baking tin (see Note below for size options) and smooth out using a silicon spatula
  • OPTIONAL: pour over 480 g chocolate200 g carnation caramel and spread it on top of the rice crispie mixture for a caramel layer - refrigerate for 1 hour before next step if choosing to add caramel layer
  • Whilst the base is setting in the fridge, heat 480 g chocolate in Bain-Marie (or microwave) until melted, then pour and spread it over the krispie base (or caramel layer)
  • T hen refrigerate for 2 hours (minimum) before cutting up. Portion up into squares (see note below), slices or however you like and enjoy!

Notes

Heating Mars Bars and Chocolate
Bain Marie: place a bowl on top of a pot with water simmering underneath - but ensure the water is not touching the bottom of the bowl. The will provide slow, gentle and continual heat to the mixture.
Microwave: if you want to heat the chocolate using a microwave instead - microwave for an initial 40 seconds and then 10-20 second bursts thereafter, stirring each time. If you cook too quickly, the chocolate will burn and clump together.
Cake Tin Sizes
For the high height Mars Bar Cake it's: 20cm x 20cm x 5cm  (8in x 8in x 2in)
Or for lower height version: 22cm x 31cm x 4cm (8.5in x 12in x 1.5in) 
Cutting the Mars Bar Cake 
It's easiest to cut the tray bake into slices or squares if the Mars Bar Cake is at room temperature. Using a hot knife (dip in boiling water and wipe clean between slicing) will ensure uniform slices. And if you're worried it may melt the chocolate a little, then you could turn the traybake either upside down or on its side to cut. If you've included the caramel layer, this will be more difficult.

Nutrition

Calories: 493kcalCarbohydrates: 61gProtein: 5gFat: 28gSaturated Fat: 15gPolyunsaturated Fat: 2gMonounsaturated Fat: 9gTrans Fat: 0.4gCholesterol: 22mgSodium: 224mgPotassium: 241mgFiber: 3gSugar: 41gVitamin A: 1368IUVitamin C: 11mgCalcium: 42mgIron: 6mg
Keyword chocolate tray bake, mars bar cake, mars bar slice, mars bar tray bake, rice crispie cakes, tray bake cakes
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