Mars bar slice (chocolate caramel rice krispie treats)

Mars bar slice are a super simple no bake treat that's a popular bake sale or party choice, as it's always sure to go! Tasty flavors, easy to make and no-bake, it's a great combination.

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Slices, bars, tray bakes - whatever you call them, which varies by country, these slabs of sweet goodness are always favorites for birthday parties, bake sales and more. Many are easy, without too many ingredients, and sometimes no bake, too, like lemon slice and chocolate tiffin.

This mars bar slice is another such no bake treat and a classic in both Australia/New Zealand and the UK. I'm not sure quite why it doesn't appear to have caught on in the US, but I do know it has been popular with all I've shared it with. So join me in making it, wherever you are!

What's in this no bake treat?

I'm going to start by clarifying the ingredients which may get confusing, but bear with me. You only need a short list, but the names vary depending where you are:

• Mars bars/milky way bars - in the UK/Australia (and most other countries) you are looknig for mars bars. In the US, you are looking for milky ways. In all cases, it's the candy that has a layer of fluffy nougat, topped with caramel and wrapped in chocolate.
• Rice krispies/rice bubbles - rice krispies in most parts of the world, rice bubbles in Australia/New Zealand. The plain puffed pice cereal - I have seen some use the chocolate version though I don't see it as being needed given the other ingredients.
• Butter - one all agree the name on! I recommend unsalted for this.
• Chocolate - most typically you use milk chocolate for this, but you could use dark chocolate if you prefer (or eg semi-sweet) to be slightly less sweet.
• Coconut oil/copha - copha is the Australian/NZ brand name for a vegetable shortening that's primarily made with coconut oil. Elsewhere, coconut oil is fine - I'd suggest refined so there's not the coconut flavor.

A little history...

This treat may not have a clear history itself, but it does come with some interesting side-history. Firstly, Mars bars were first made in Slough, England, in 1932 by Forrest Mars Sr, the son of Frank Mars who started the Mars company in the US. Forrest Mars modeled the bar on his father's Milky Way which was already popular (released in 1924).

To make things even more confusing, the name mars bar was used in the US, but the confection had added almonds. This bar was discontinued and reinvented as the snickers that exists today. Milky way was introduced in the UK, and still exists, but that bar doesn't have the caramel layer and is a bit fluffier. The equivalent in the US is 3 Musketeers.

Next is the idea of using cereal in sweet treats - it appears it may have first been an Australian thing with certainly the first that grew popular being chocolate crackles that first appeared in Australian Women's Weekly in 1937. This pre-dates two Kellog's home economists creating rice krispie treats as a promotional tool for the cereal in 1939.

Chocolate crackles use rice krispies/bubbles, sugar, copha, coconut and cocoa powder. In the 1950s, Kellog's Australia trademarked the name and started using the treat as a marketing tool, much as rice krispie treats are in the US. While it's not completely clear who or where mars bar slices emerged, it appears to have been in the 1970s and likely as an evolution of this treat.

Tips for making this treat

Despite all the potential confusion in the names etc, this is a very easy treat to make. But I would give a couple quick tips:

• Line the baking pan/tin with parchment - this will make it much easier to take out and then slice as a block. Do this before you start.
• Melt the butter and mars bars/milky way over a medium-low heat and even better, in a non-stick pot/pan. This helps avoid too much sticking, possibly burning etc
• Once you add the rice krispies/bubbles, work quickly to mix and transfer the mixture. As it cools, it will firm up, so you want to spread it out and flatten a little before it's too firm.
• Let it firm up before cutting - you want the chocolate to have solidified again before you cut into pieces. That said, you might then want to leave it out a minute first. The coconut oil/copha does help avoid cracking compared to just plain chocolate. But a couple minutes at room temperature and a warm knife help further.

It really is incredibly easy, though, with just a short bit of melting, mixing and waiting for it to firm up. And like other treats made in a block like this, you can easily adjust portion size to suit your needs.

Storage tips

This is best stored in the fridge, especially if it's a bit warm to help avoid the chocolate melting. Though it will also keep at a cool room temperature. Store in an airtight container - I recommend separating layers with parchment though it may not be strictly needed. As with other treats made with rice cereal, it will get a bit less crisp over time, but it should be fine for a good 3 - 5 days or even slightly more.

Mars bar slice is a wonderfully easy, tasty treat that comes together in no time. It's perfect for parties, bake sales or just because and will likely disappear fast. Whether it brings back a bit of nostalgia for you, as for me, or not, it's well worth giving a try.

Try these other tasty no bake treats:

• Peppermint slice - with tasty layers of a cookie/biscuit base, peppermint fondant and chocolate, it's another classic slice/bar/tray bake.
• Chokladbollar, Swedish chocolate oat balls - a family favorite and so easy to make.
• Cranberry truffles - a great twist on a classic, especially good for the festive season.
• Plus get more snack recipes, both sweet and savory, Australian recipes and British recipes in the archives.

I use this 9x9 inch square baking pan for this that works well (and has a lid, handy for storing any leftovers; affiliate link).

See some of my favorite cooking tools and ingredients in the Caroline's Cooking Amazon store. 

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