These Mummy Mars Bar Slices are a Halloween twist on a proper Scottish favourite. Chewy, crispy Mars Bar Slices are cut into squares, drizzled with white chocolate bandages and finished with edible eyes. They’re completely no-bake, easy to make, and a fun Halloween treat for kids to help decorate.
Mummy Mars Bar Slices Recipe Snapshot
- Recipe Type: Mummy Mars Bar Slices – a Halloween twist on a classic Scottish Mars Bar Slice.
- Difficulty: Very easy – no oven required!
- Makes: 12 slices.
- Prep Time: Around 20 minutes, plus decorating.
- Setting Time: At least 2 hours for the Mars Bar Slice base, plus time for the chocolate to set.
- Base: Mars Bars, margarine/butter and Rice Krispies.
- Texture: Crisp and chewy.
- Decoration: White chocolate bandages finished with edible eyes.
- The Trick: Keep the heat low when melting the Mars Bars and work fairly quickly once the Rice Krispies are added, as the mixture becomes harder to press into the tin as it cools.
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What are Mummy Mars Bar Slices?
Mummy Mars Bar Slices are a Halloween twist on my classic Scottish Mars Bar Slice. They’re made by melting Mars Bars with margarine/butter, stirring through Rice Krispies and pressing the mixture into a tin to set. Once firm, the tray bake is cut into squares and decorated with white chocolate bandages and edible eyes to create little mummies.
In the US, you may see similar treats described as Mummy Rice Krispie Treats, although this recipe is a little different from the marshmallow-based versions, like my Monster Rice Krispies Squares. The chewy, crispy base comes from Mars Bars rather than marshmallows. And if you’re baking in the US, Milky Way bars are the closest equivalent to a UK Mars Bar and have also been tested successfully in this recipe. Just be aware that US Milky Way bars are not the same as the Milky Way bars sold here in the UK!
These are another Scottish twist on Halloween baking, alongside my Pumpkin Empire Biscuits and Spider Web Biscuits.
When a Mars Bar Slice Gets Spooky
I had wanted to share another Halloween recipe, and my Monster Rice Krispies Squares were already a big hit with the kids. So I took inspiration from those and my classic Mars Bar Slice, combining the two to create these Mummy Mars Bar Slices.
They’re another Scottish twist on Halloween baking, alongside my Pumpkin Empire Biscuits and Spider Web Biscuits. The familiar Mars Bar Slice base is super simple to make, while the white chocolate bandages and edible eyes turn them into little mummies without requiring any complicated decorating – great for getting the kids involved!
Key Ingredients
These Mummy Mars Bar Slices use just a handful of simple ingredients, with Mars Bars and crisped rice cereal making up the base, and white chocolate and edible eyes creating the mummy decoration.
See the recipe card for a full ingredients list, required quantities and cup conversions.
Substitutions & Additions
Other Cereals: If you don’t have Rice Krispies, you can use Cornflakes or Coco Pops instead. I’ve made these with both, and they work well, although the finished squares will have a slightly different flavour and texture depending on which cereal you choose.
Edible Eyes: Edible eyes aren’t really essential – more of a nice extra if you have them. You can also use chocolate chips instead!
Looking for dairy-free, gluten-free or vegan adaptations? See the Free-from & Vegan section below.
Free-from & Vegan
Amy recommends: If you regularly need to adapt baking recipes for gluten-free, dairy-free, egg-free or vegan diets, I highly recommend The Elements of Baking by Katarina Cermelj, creator of The Loopy Whisk. It’s a brilliant resource for understanding how substitutions work, rather than simply swapping ingredients and hoping for the best.
Gluten-free Options:
To make gluten-free Mummy Mars Bar Slices, you’ll need to use a gluten-free crisped rice cereal and swap out the Mars Bars (which unfortunately aren’t gluten-free) for Butterm!lk Caramel Nougat Bars. Also check the chocolate and any decorations carefully too – sometimes gluten can be hiding in packaged products, so always check the individual labels when serving to those with coeliac disease.
Nut-free Adjustments:
This recipe contains no nuts, but as always, be sure to double-check the allergen lists for your individual ingredients.
Dairy-free Swaps:
To make these dairy-free Mummy Mars Bar Slices, swap the Mars Bars for Butterm!lk Caramel Nougat Bars, use a dairy-free block margarine instead of butter, and your favourite dairy-free chocolate for decorating.
Egg-Free Adaptations:
This recipe contains no eggs, but as always, be sure to double-check the allergen lists for your individual ingredients.
Vegan Substitutions:
To make this recipe vegan, simply follow the dairy-free swaps above, using Butterm!lk Caramel Nougat Bars, use a dairy-free block margarine instead of butter, and your favourite dairy-free chocolate for decorating.
Allergy Disclaimer & Resources:
Any advice or suggestions to make recipes “free-from” or vegan are purely suggestions. Please double-check all packaged ingredients individually, taking extra caution when baking for those with allergies or intolerances.
For official guidance on food allergies, please see Food Standards Agency (food.gov.uk) | For more info on coeliac disease, please see Coeliac UK (coeliac.org.uk) | For more info on a vegan diet, please see The Vegan Society (vegansociety.com)
How to Make Mummy Mars Bar Slices
Mummy Mars Bar Slices are a melt-and-mix recipe, but the Mars Bar mixture becomes sticky and harder to work with as it cools. So have your tin, cereal and spoon ready before you begin, and work quickly once everything has melted. Follow the step-by-step below, or head to the recipe card at the bottom for the full printable recipe.
- Prepare the tin: Line a 20×20cm (8×8 inch) baking tin with greaseproof paper. Set aside.
- Melt the margarine/butter and Mars Bars: Add the margarine/butter and roughly chopped Mars Bars to a medium saucepan. Melt gently over a low-medium heat, stirring regularly.
- Add the cereal: Once the Mars Bars and margarine/butter have melted together, remove from the heat and add the crisped rice cereal. Stir until the cereal is well coated.
- Press into the tin: Transfer the mixture to your prepared tin and press it evenly into the corners. Work fairly quickly, as the mixture becomes more difficult to press as it cools.
- Leave to set: Place the tin in the fridge and leave to set for at least 2 hours. Once firm, cut into 12 squares and place them on a sheet of greaseproof paper.
- Melt the white chocolate: Melt the white chocolate over a bain-marie or in short bursts in the microwave, stirring regularly.
- Decorate the mummies: Drizzle or pipe lines of white chocolate over each slice to create the mummy bandages. Use a little melted chocolate to stick on two edible eyes, then leave to set again before serving.
Top Tips for Mars Bar Slice Mummies
- Have Everything Ready: The Mars Bar mixture starts to set as it cools, so have your tin, crisped rice cereal and spoon ready before you begin melting.
- It Won’t Melt Smoothly: The nougat doesn’t melt in quite the same way as the chocolate and caramel, so the mixture will always look a little lumpy. You can break it up slightly with the back of a spoon or spatula, but don’t worry – once the Rice Krispies are mixed in, everything will combine nicely.
- Use a Low Heat: Too much heat can cause the chocolate to seize or burn. Gentle heat and a bit of patience will give you the best texture for your Mars Bar Slice base.
- Mix Quickly: The Mars Bar mixture starts to set as it cools, so stir everything together straight away and press it into your tin while it’s still warm.
- Let the Base Set Completely: Leave the Mars Bar Slice base to set until it is firm before cutting and decorating. This helps the squares hold together more easily as you cut them.
- Drizzle How You Like: A spoon works perfectly well for creating messy mummy “bandages”, but if you want a neater finish, spoon the melted chocolate into a piping bag and drizzle it across the slices.
- No Eyes? No Problem: Edible eyes are a fun extra, but chocolate chips work just as well for creating the mummy eyes.
Storage, Freezing & Make Ahead
- Storage: Once decorated and fully set, store your Mummy Mars Bar Slice in an airtight container at room temperature. They will keep well for up to 1 week. If your kitchen is particularly warm, you can keep them in the fridge, but I’d recommend allowing them to return to room temperature before serving for the best texture.
- Make Ahead: These can be made ahead of time and stored in an airtight container until you’re ready to decorate and serve them, making them particularly handy for Halloween parties and school events. You could even make the Mars Bar Slice base ahead of time and then let kids decorate them as an activity at parties or clubs.
- Freezing: Mummy Mars Bar Slices can be frozen for up to 3 months. Store them in an airtight container, separating layers with greaseproof paper to prevent them from sticking together. Allow them to thaw at room temperature before serving.
Mummy Mars Bar Slices FAQs
Yes. These are completely no-bake treats. The Mars Bars and margarine/butter are melted on the hob or in the microwave, then mixed with Rice Krispies and left to set in the fridge before decorating.
If you’re baking in the US, yes, you can use Milky Way bars as the closest equivalent to UK Mars Bars. I’ve tested them successfully in this recipe. But just remember that US Milky Way bars are not the same as the Milky Way bars sold in the UK.
The nougat in Mars Bars doesn’t melt in quite the same way as the chocolate and caramel, so the mixture may still look a little lumpy. This is normal. Break up any larger pieces with the back of a spoon or spatula, then add the Rice Krispies – everything will combine as you mix.
Yes. Other crisped or puffed rice cereals can also be used in this recipe, as well as Coco Pops and Cornflakes. Rice Krispies are the obvious choice, but supermarket own-brand versions are also suitable.
More Halloween Baking
If you loved these Mummy Mars Bar Slices, here are some more of my favourite Halloween baking recipes for you to try next:
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Mummy Mars Bar Slices
INGREDIENTS
- 115 g Block Margarine or Butter
- 230 g Mars Bars (roughly chopped)
- 130 g Crisped Rice Cereal (eg. Rice Krispies)
- 150 g White Chocolate
- 24 Edible Eyes
EQUIPMENT
INSTRUCTIONS
- Line a 20×20cm (8×8 inch) baking tin with some greaseproof paper and set aside.
- In a large saucepan, melt the butter/margarine and Mars Bars over a low-medium heat. Use the back of a spoon or spatula to break up the nougat.
- Remove from the heat, add the crisped rice cereal to the melted mixture, and mix well to ensure the cereal is fully coated.
- Transfer the mixture into your prepared baking tin and push down with the back of a spoon, ensuring an even finish right into the corners. Allow to set for at least 2 hours before decorating.
- Once set, cut into 12 sqaures. Place a sheet of
greaseproof paper ready for decorating. - Melt the white chocolate over a bain-marie, or in short bursts in the microwave. Pipe or drizzle the chocolate over your Mars Bar slices to look like bandages. Using a small amount of melted chocolate, stick the edible eyes onto the Mummy Mars Bar Slices.
- Allow the chocolate to set completely before enjoying.
IMPORTANT NOTE:
All my recipes are developed using a digital scale and the metric system (grams and millilitres). Cup measurements are available as a conversion, but these, unfortunately, won’t always be as accurate. For best results, I always recommend baking with a digital scale.
RECIPE NOTES:
LIKE THIS RECIPE?
Leave a comment and rating below!Originally published in October 2023.
ABOUT THE AUTHOR
Amy Beth Reid
Amy Beth Reid is an award-winning food blogger, mother, wife and cookbook author. Inspired by her childhood in the kitchen with her Mum – a professional baker and her children’s Granny – Amy now shares her tried-and-tested traditional home baking recipes with bakers of all abilities around the world. She lives in Scotland with her husband, two sons and her small pack of Siberian huskies.