Mars bar slice was the rice krispie treat that I grew up with. Rice krispies mixed with melted Mars bars, for a gooey caramel base, and topped with a layer of chocolate!
Easy to make, no bake, crunchy, and decadent Mars bar rice krispie treats
But imagine a rice krispies treat, but instead of marshmallows, you get melted caramel, nougat, and chocolate from Mars bars… These crunchy rice krispies treats are decadent and impressive. And they are super easy to make too.
Ingredients to make Mars bar slice
- Mars bars (also known as Milky way in the US, but the Mars bar sold worldwide is much better in terms of flavor, in my opinion).
- Rice krispies
- Semisweet chocolate chips – for the topping
- Coconut oil or butter – for the topping
The topping is optional, but these no bake slices just aren’t complete without a generous layer of chocolate on top!
Making the Mars bar slice recipe
Super easy. I made these often as a kid, so it even feels ridiculous to call this a recipe. But here goes…
Line an 8 or 9 inch square pan with parchment paper and set aside.
Cut the mars bars and place them in a pot, along with the butter. I also like to add some salt, which helps balance the sweetness. Heat the pot over medium / medium high heat and stir to melt the ingredients. Stir the mix frequently to prevent the melted chocolate mix from burning.
When the chocolate bars have melted and the mix is smooth, add all the rice krispies and quickly mix it in until it’s all evenly coated.
While still warm, scrape the mixture into the prepared pan. Press it into the pan to form an even layer. This is the bottom layer of your mars bar slice.
To make the chocolate layer – melt the chocolate and coconut oil (or butter) until smooth. You can do this in the microwave in small bursts, or melt the chocolate over a double boiler.
Pour the smooth chocolate mix over the surface of the mars bar rice krispie treat layer, and smooth it out with an offset spatula.
Refrigerate until the mars bar slices have cooled and are set. Once set, they can be removed from the pan and cut into squares.
Tips for cutting Mars bar slices
- Let the bars come to room temperature, so that they are easier to cut through.
- Use a sharp, clean, warm knife to cut the slab into squares. The warm blade helps cut through the chocolate layer.
- Wipe the blade clean between cuts.
Storing the slices for later
I’ve kept these mars bar slices in an air-tight container and in the fridge for over two weeks. They keep really well.
But do let them rest at room temperature for a bit before eating. This lets the Mars bar rice krispie layer soften a little.
You could also store these in the freezer for up to 6 months. Then let them fully thaw out before eating.
Final recipe notes
These no bake rice krispie bars are a nostalgic shout out to my childhood! I loved making Mars bar slices because they were addictively delicious, and so easy to make.
These are great for gift giving during the holidays too! They make the perfect addition to treat boxes during Christmas or special occasions.
Mars Bar Slice (Mars Rice Krispie Treats)
Mars bar rice krispie layer
- 260 g Mars bars 5 x 52 g
- 115 g butter ½ cup / 1 stick (salted or unsalted)
- ¼ tsp sea salt Only if using unsalted butter
- 110 g rice krispies 3 ½ cups
- 300 g semisweet chocolate
- 15 g coconut oil about 2 tbsp
- ¼ tsp sea salt
Mars bar rice krispie layer
- Line an 8 or 9 inch square pan with parchment paper.
- Cut the mars bars into pieces (1 – 2 inch pieces are fine), and place them in a large saucepan (enough to fit 3 ½ cups of rice krispies).
- Add the butter and salt (only if using unsalted butter).
- Heat the candy bars, butter, and salt mix over medium heat while stirring until everything is dissolved and the mix is smooth. Make sure the mix doesn't burn at the bottom.
- Once the mixture is melted and smooth, turn off the heat, and add the rice krispies.
- Quickly mix in the rice krispies until it’s all evenly coated.
- Remove the pot from the stove, and scrape the rice krispie mix into the prepared pan. Using a spatula, press the mixture into the pan to get an even layer.
- Set aside until you prepare the chocolate layer.
- Place the chocolate, salt, and coconut oil in a microwave-safe bowl. Heat in the microwave in 20 – 30 second bursts, while stirring in between, until the chocolate is about 80% melted.
- Continue to stir the mix until all the chocolate is melted. The chocolate mix is now ready.
Assembly and cutting the Mars bar slice
- Pour the chocolate topping over the rice krispie layer. Use an offset spatula to evenly spread the chocolate layer.
- Let the two layers set. You can transfer this to the fridge to let it chill faster.
- When the mars bar slice is set, remove it from the pan. If the slice is very cold, let it soften to room temperature a little, as it will be easier to cut then.
- Using a sharp knife, cut into portions. I prefer to cut the slice into 16 portions (about 2 x 2 inches per piece). But feel free to cut them into any size you like.
- Store these slices in an airtight container. Place parchment paper or wax paper between layers to prevent sticking.
- These will keep in the fridge for at least 2 weeks, and up to 6 months in the freezer.
- Allow the slices to come to room temperature before eating, for the best flavor and texture.
“This website provides approximate nutrition information for convenience and as a courtesy only. Nutrition data is gathered primarily from the USDA Food Composition Database, whenever available, or otherwise other online calculators.”