Skip to main content

  • Nut free
  • Peanut free
  • Sesame free
  • Shellfish free
  • Seafood free
  • Vegetarian

Mars bar slice is a classic Aussie childhood treat that is great for birthday parties or making with kids.

  • Serves24
  • Cook time10 minutes
  • Prep time15 minutes
Mars bar slice


  • 3 cups (105g) Rice Bubbles
  • 240g Mars bars, chopped
  • 100g butter, chopped
  • 1/4 tsp sea salt flakes
  • 100g dark chocolate, chopped
  • 100g milk chocolate, chopped

Nutritional information

Per serve: Energy: 582kJ/139 Cals (7%), Protein: 1g (2%), Fat: 8g (11%), Sat Fat: 5g (21%), Sodium: 61mg (3%), Carb: 15g (5%), Sugar: 10g (11%), Dietary Fibre: 04g (1%).

Check ingredient labels to make sure they meet your specific dietary requirements and always consult a health professional before changing your diet. View dietary information here.

Percentage Daily Intake information on our recipes is calculated using the nutrition reference values for an average Australian adult.


  1. Step 1

    Grease the base and sides of a 19cm x 29cm slice pan and line with baking paper, allowing the sides to overhang.

  2. Step 2

    Place the Rice Bubbles in a large bowl.

  3. Step 3

    Combine the Mars bars and 75g of the butter in a medium saucepan over low heat. Cook, stirring, for 10 mins or until butter melts and mixture is smooth. Remove from heat. Stir in salt.

  4. Step 4

    Pour the Mars bar mixture over the Rice Bubbles and stir until well combined. Spoon into the prepared pan and use the back of a spoon to smooth the surface. Set aside for 1 hour to cool completely.

  5. Step 5

    Place the combined chocolate and remaining butter in a heatproof bowl over a saucepan half-filled with simmering water. Stir until smooth and combined. Pour chocolate over the top of the slice to evenly coat. Set aside for 30 mins or until set. Cut into squares or slices to serve.

Recipe tip

Jazz your slice up by decorating it with chopped nuts, coconut flakes or pretzels.

Cook. Store. Save.
Clever storage
Store Mars bar slice in an airtight container in your fridge for up to 1 week.

Use it up
Mars Bar slice is a great way to use up leftover chocolate from Easter or other baking. You will need around 5 full-sized Mars bars to make 240g or you could buy a 20 piece bag and add the rest to lolly bags if you’re making the slice for a party. 

Mars bar slice recipe

If you have never tried this delectable treat, you will fall in love with this easy Mars bar slice recipe. Made from only a few simple ingredients, it’s a great way to use up leftover chocolate. 

How to make Mars bar slice

One reason this treat is so widely loved is because of just how easy it is to whip up. Each recipe for Mars bar slice is a little different, but it generally includes a base of Rice Bubbles, the popular chocolate bar melted with butter or oil, and then topped with melted chocolate. 

The best Mars bar slice will only take you about 5-10 minutes to prepare and then the hardest part is waiting for the slice to cool!

Start by lining your slice pan with baking paper. If you grease or spray the pan prior to lining, this helps the baking paper to stick and makes it easier when pressing the mixture into the base of the pan. Ensure the paper overhangs the sides to assist with removing the prepared slice. 

With your baking tray lined and ready to go, you can start preparing the slice. Melt Mars bars in a  saucepan with 75 grams of the butter until the mixture is glossy and smooth. Pour into a bowl with the Rice Bubbles and combine until the Rice Bubbles are completely coated in the mixture. Spoon the mixture into the lined pan and smooth it out using the back of a metal spoon, until it reaches all of the corners and you have a smooth and even surface. Then put it aside to cool completely. 

Once the Rice Bubble mixture is almost cooled, melt the extra chocolate with the remaining butter in a heatproof bowl over a simmering pan of water until smooth and glossy. Pour the melted chocolate mixture over the top and smooth around until all of the Rice Bubble mixture is covered. Set aside until the chocolate is fully set before cutting into portions. 

The easiest way to cut the slice is to remove the whole thing from the pan and place onto a chopping board before slicing into squares or rectangles.  

Variations on Mars bar slice

Whilst the regular Mars bar slice with Rice Bubbles is perfect as is, you can play around with the flavours to suit your tastes or dietary needs. To create a gluten-free Mars bar slice you could replace the Rice Bubbles with a gluten-free version, Honey-O cereal or your favourite gluten-free cereal. 

Want to give your slice an extra chocolate boost? Use Cocoa Pops or similar chocolate cereal. You could also experiment with different kinds of chocolate to put on top. Whether you’re using up leftover chocolate or just want to try something different, you could opt for all dark or all milk, or change the ratios to suit your tastes (or what’s available). If using white chocolate instead of milk and dark, you will need to be careful when melting it to ensure it doesn’t seize. 

You could also add extra chocolates or treats on top and create the ultimate Mars bar slice – pretzels, leftover Easter eggs or mini Oreos would all make a great topping idea.

Now get cooking

Now that you know how simple it is to create this decadent treat, you can make it anytime you crave something sweet. Once you have mastered the sweet slice, why not try Curtis Stone’s brown butter and salted caramel slice, peanut butter and cookie brownie or more decadent chocolate desserts.