This chewy, chocolate Mars Bar Slice Recipe is one of the best things to come out of the 1980s.
It's a no-bake recipe and is so easy and simple. The only challenge is to stop eating after one slice!
There are so many slight variations of this recipe. But I'm here to convince you that this one is the ultimate Mars Bar Slice recipe:
- I've done my research! This recipe has been adapted from the recipe my mum used when I was a kid and others I've tried since then. And I've tried more than a few!
- It's a slice that's not too crunchy and not too crumbly. A few little tweaks I've come up with over the years, means this recipe avoids those things that disappoint a true Mars Bar Slice connoisseur.
- It'll look as good as it tastes – nice and neat just like the picture above – if you follow the instructions below.
Ready? Just gather the 5 ingredients and you'll have it ready in 20 minutes flat.
To make this recipe, you'll need:
- Mars Bars
- Rice Bubbles (you might call them Rice Krispies or Ricies if you're not from the land down under)
- golden syrup (you can substitute agave nectar, cane syrup or brown rice syrup)
- milk chocolate.
The exact measurements can be found in the recipe card at the bottom of the post.
TIP: Thanks to the ever-shrinking size of a Mars Bar, you'll now need 4 ½ Mars Bars rather than 4 as pictured above. The recipe will still "work" with 4 of the new smaller-sized Mars Bars, but I recommend using 4 ½.
Apart from the ingredients, you'll also need:
- slice tin (around 27 x 17cm), greased and lined
- mixing bowl and spoon
- small whisk
- small heatproof bowl and spoon
You use the stovetop and also the microwave when preparing the slice.
TIP: When greasing and lining the tin, leave some baking paper overhanging on each side so you can gently ease the slice from the tin to cut it up. This avoids the difficulty of trying to cut it into squares while still in the tin. So much easier to just lift it out and cut it up!
How to make Mars Bar Slice
Okay, let's go.
Start by measuring out the rice bubbles into a large mixing bowl.
Break up the mars bars into pieces and add the mars bars, butter and syrup to a saucepan.
Heat the ingredients in the saucepan gently over low heat until they're melted and keep stirring until the mixture reaches a smooth, runny consistency.
I swap the spoon for a small whisk towards the end of the process to get a super smooth consistency.
You then pour this mixture into the rice bubbles and stir quickly to combine.
Into the slice tin
Spread it into the greased and lined slice tin and use the back of a spoon to smooth it out evenly. Make sure you press it firmly into the tin at this step.
Melt the milk chocolate in the microwave using 20 second bursts. Take out and stir for 20 seconds between each burst until you have a runny, smooth melted chocolate.
Pour the melted chocolate over the slice to form the top layer.
Tilt the tray from side to side if necessary to ensure the entire top layer is covered in chocolate.
Next, it's into the fridge to set.
Be patient! It won't be long and you'll be enjoying a slice or two.
When the slice has set (it'll take a few hours) and you're ready to cut it into squares, take the slice out of the fridge and leave it for about 20 minutes.
If you try to cut it up straight from the fridge the top chocolate layer may crack.
Once you've left it out for at least 20 minutes, ease it from the tray using the overhanging baking paper.
Cut into squares using a large, sharp knife.
While it's a fairly straightforward process, keep these four tips in mind to totally nail this recipe:
1. Use good quality, fresh ingredients
There are only a few ingredients, so use the best. I use Cadbury chocolate, real Mars Bars, Kellogg's rice bubbles, and other brand names.
2. Use a whisk to get a super smooth melted mixture
When melting the butter, golden syrup and Mars Bars together, the mixture can tend to be clumpy. Make sure you use a whisk to stir it towards the end of the melting process and get a super smooth result every time.
3. Use a spoon for an even finish
After pressing the mixture into the tray, use the back of a metal spoon to flatten the slice evenly on top. Make sure you press it firmly into the tin.
4. Don't cut the slice straight from the fridge
Avoid cracking in the top layer by allowing the slice some time at room temperature before cutting into squares.
It's best stored in the fridge, especially during the summer months.
However it is okay at room temperature for a while if you're planning to take it to a party to share, for example.
It will last at least a couple of weeks stored in an airtight container in the fridge.
The original is really hard to improve upon, it's just so good as it is.
However, some people like to add mini marshmallows, Maltesers or M & Ms to the mix.
You can stir these into the rice bubble mixture or sprinkle over the top of the top melted chocolate layer.
At Christmas, I like to buy some Christmas-themed M & Ms and sprinkle over the top to add a festive touch.
Mars Bar Slice FAQs
You can. It should be okay for a month or two in the freezer if wrapped or placed in an airtight container. This slice gets gobbled up too quickly in our house for freezing, though.
If you do manage to freeze some, remove from the freezer and allow to defrost before consuming.
You can replace the golden syrup with maple syrup, honey or corn syrup. You can also simply omit it. I prefer the flavour and consistency of mars bar slice with golden syrup.
If your slice is crumbling you may not have pressed it into the tin firmly enough.
It's also possible you didn't melt and combine the mars bar, butter and syrup mixture well enough. Make sure these ingredients are melted and combined over low heat until smooth.
If it cracks as you cut it, it's too cold. Leave the slice out of the fridge for at least 20 minutes before cutting into squares.
If the slice is too hard to eat, let it soften out of the fridge for about half an hour before consuming.
More sensational slice recipes
There are so many wonderful recipes in the slice collection. Here are four of my favourites:
Mars Bar Slice
- slice tin (around 27 x 17cm)
- mixing bowl and spoon
- small whisk
- small heatproof bowl and spoon
- 4 Mars bars (53 gram bars) (that's 4 ½ of the new 47 gram bars)
- 3 cups rice bubbles (100 grams)
- 60 grams butter
- 2 teaspoons golden syrup
- 240 grams milk chocolate (you can get away with 180 grams, which is one family block of Cadbury's, but the extra 60 grams is ideal)
- Grease a slice tin (around 27 x 17cm) with butter and then line with baking paper, leaving extra on each side (to pull the slice from the tin once cooked).
- Measure rice bubbles into a large mixing bowl.
- Break mars bars into pieces with your hands and put into a saucepan. Add butter and golden syrup.
- Place saucepan on low heat while stirring to combine.
- Keep stirring until the mixture reaches a smooth, runny consistency. Use a whisk to stir the mixture towards the end of the process to help get that completely smooth consistency. The mixture should resemble melted chocolate, with no lumps.
- Add mixture to rice bubbles and stir quickly to combine.
- Spread out mixture in the slice tin, spreading evenly to the edges and then pressing into the tin firmly with the back of a metal spoon.
- Melt chocolate in the microwave using 20 second bursts. (check and stir after each burst).
- Pour melted chocolate over the slice and angle tin from edge to edge to help chocolate reach each side and corner of the slice tin.
- Place in fridge for 15-30 minutes. Ideally, the chocolate shouldn't be completely set when cutting (it will crack as you're cutting if it's too hard). Alternatively, if you've left the slice in the fridge for longer just let the slice rest at room temperature for at least 20 minutes before cutting into squares.
- Remove slice from tin by lifting edges of baking paper, cut into squares and return to the fridge.
- Read the entire post and recipe card for all the tips and hints. This is an easy recipe, but there are a few tips and tricks to get a perfect result.
- The most important part of the process is heating the mars bars, syrup and butter gently and then whisking the mixture over the low heat to get a smooth texture. Make sure the temperature remains low.
- Another tip for perfect Mars Bar Slice: make sure you use fresh, good quality ingredients.
- Can you replace the golden syrup? Yes, with maple syrup, honey or corn syrup. You can also simply omit it.
- Make it festive by adding some red and green M & Ms or festive-themed sprinkles.