Name: Mars bar slice recipe
Prep time: 5 min
Cook time: 10 min
Total time: 15 min
Yield: 12
Ingredients: 3 x 65 g Mars Bars chopped; 90g Essentials Unsalted Butter, chopped; 3 cups Rice Bubbles; 200 g Baking Milk Chocolate

by tan73 Last updated on 02/02/2026

What’s better than a Mars bar? A Mars bar slice that’s what. Containing all the features you love about the iconic snack bar — gooey caramel, chocolate and nougat — this recipe adds an extra crispiness through rice bubbles, richness through butter and even an extra layering of chocolate over the top. Why not, right? What’s more, it’s prepped and ready to set in the fridge in just 15 minutes.

How to make this 4-ingredient Mars bar slice: key tips

Make sure you combine the Mars bar and butter over low heat. You don’t want the chocolate to scorch. There may still be little specks of unmelted nougat but that’s okay. When transferring to the prepared pan, press the mixture in well. You can do this with a spatula or place a piece of non-stick baking paper over the top and use your hands to smooth and press down. This prevents the slice from crumbling when cut into pieces.

Key ingredients in our easy Mars bar slice recipe

Our best Mars bar slice recipe uses baking chocolate for the topping. Also sold as cooking chocolate, it is less sweet than eating chocolate, making it the perfect addition to the already sweet Mars bar slice. Although it won’t make a huge difference, try to use unsalted butter as Mars bars already contain salt. We love using our favourite snack bars in recipes, like Bounty, Violet Crumble and Cherry Ripe or check out some more for Mars bar recipes!

- Australia's Best Recipes Team

Ingredients

3 x 65 g Mars Bars chopped
90g Woolworths Essentials Unsalted Butter, chopped
3 cups Kellogg's Rice Bubbles
200 g CADBURY Baking Milk Chocolate

Method

Step 1

Grease a slice tray.
Step 2

Combine Mars Bars and butter in a saucepan. Stir constantly over low heat, without boiling, until the mixture is smooth.
Step 3

Stir in Rice Bubbles and press mixture evenly into greased tray.
Step 4

Melt the chocolate in the microwave on a low setting, stirring every 20-30 seconds.
Step 5

Spread the chocolate evenly over the slice mixture and refrigerate until topping is set.

Recipe Notes

from Australia’s Best Recipes team

What is baking chocolate?

This Mars bar recipe uses baking chocolate for the topping. Your go-to snacking chocolate has added sugar and milk in it plus flavourings like vanilla to make it a melt-in-your-mouth tasting experience. We already have a fair bit of sugar in the Mars bars, so using an eating chocolate would make the slice too sweet. Although baking (also sold as cooking) chocolate still has sugar and sometimes milk in it, it is a purer chocolate and perfect to adorn this decadent slice.

How do I cut my mars bar slice?

After spending time in the fridge, your Mars bar slice sets pretty solidly, so it’s best to take it out about 20 minutes before you intend to cut it, this will stop the chocolate top from shattering. Make sure when you grease and line the pan, you allow the baking paper to overhang the sides. Hold the paper and gently ease the slice from the pan, then use a long sharp knife to cut into the desired sizes. If the slice is still a bit hard to cut, run the knife under warm water and then wipe clean with a tea towel. The warmth helps the knife just glide through the sticky slice.

Can I freeze Mars bar slice?

Mars bar slice will last for a week if stored in an airtight container in the fridge. If you make a double batch or like to have some on hand for spontaneous morning or afternoon teas, Mars bar slice freezes well. Cut the slice into pieces and place on a tray in the freezer. Leave until partially frozen and then place in a single layer in a large snaplock bag or layered in an airtight container using baking paper in between the layers. The pieces won’t take long to defrost at room temperature and are, actually, quite nice eaten a bit frozen.

How do you stop the slice from being crumbly?

If your slice is crumbly, you may not have pressed it into the pan firmly enough. It’s also possible you didn’t melt the Mars bar and butter mixture until well combined. Make sure these ingredients are cooked well over low heat until smooth. The Mars bars will never completely melt. If there are tiny flecks of unmelted nougat it’s okay. Once the mixture is melted and combined, don’t continue to heat, or the butter may split away from the chocolate. Remove from the heat and immediately stir in the rice bubbles.