This deliciously crispy Thermomix Mars Bar Slice is made from only five ingredients and takes ten minutes to prepare. There is no baking involved, and it makes the perfect chocolatey, crunchy and sinful snack.

We love a no bake treat here - there's no watching the oven and there's less risk of baking failures. This is an excellent recipe for children's birthday parties and special occasions. You can make it in advance, as it lasts up to a week in the fridge or three months in the freezer.
If you also love a recipe that doesn't require baking, check out our 3-Ingredient Oreo Balls and Chocolate Covered Strawberries.
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Why You'll Love It
- Five simple ingredients.
- Ten minutes to make with minimal preparation.
- A sweet, delicious treat.
- Keeps well in the fridge or freezer.
Ingredients
Note: The full ingredients and quantities are shown in the recipe card below.
Mars Bars - use the 47g Mars Bars if you can find them. If not, any size Mars Bars will do as long as the total weight is 190g.
Rice Bubbles - called Rice Krispies, in the UK.
Butter - use unsalted.
Milk chocolate - use baking chocolate melts. Excellent quality brands are Cadburys or Nestle. I don't recommend home-brand baking chocolate for this recipe, as the taste is not good. Also, it's important not to use normal milk chocolate, as it won't set properly.
Vegetable oil - add a little to the melted chocolate to prevent the topping from cracking.
Step by Step Instructions
Note: This is a summary of the instructions. The full ingredients and instructions are shown in the recipe card below.
For the Crispy Base
Step 1. Line a 20cm (8") square tin with baking paper and set aside.
Step 2. Slice the Mars Bars into 2cm pieces and add them to the Thermomix bowl, then add the butter and pinch of salt.
Step 3. Melt for 5 minutes until the Mars Bars melt. Scrape down the bowl and stir the mixture with a spatula. If the Mars Bars don't melt completely, that's okay.
Steps 4-5. Add the Rice Bubbles to the mixture and stir on reverse speed for 20 seconds. Give the mixture a good stir to incorporate any stray Rice Bubbles.
Step 6. Tip the mixture into the tin, press down firmly and evenly with the back of a spoon - don't forget the corners! Place in the fridge to set whilst you make the chocolate topping.
For The Chocolate Topping
Step 1. Grate and melt the chocolate in a clean Thermomix bowl.
Step 1. Pour the chocolate over the crackles, level with a spoon, and put it in the fridge for 2-3 hours or overnight.
Top Tip: Make hot chocolate with the leftover chocolate in the Thermomix bowl! Simply add milk and heat it for 3-4 minutes, then mix for 30 seconds on speed 9, so it's frothy.
Serving Suggestions
Take the Mars Bar Slice out of the fridge 30 minutes before serving. Cut into squares or slices with a warm knife.
FAQs & Expert Tips
Vegetable oil added to the melted chocolate helps the chocolate not crack. Also, warming a sharp knife in hot water before you cut it helps.
Yes, you can! Simply swap with the same quantity of Rice Bubbles.
It will keep for up to a week in the fridge - if it lasts that long!
Yes, it can be frozen for up to 1 month.
Leave it to soften at room temperature on the bench top half an hour before consuming.
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📖 Recipe
Thermomix Mars Bar Slice
A crispy, crunchy delicious treat that is perfect for birthday parties or lunchboxes.
Ingredients
- 4 x 47g Mars Bars. If you can't find 47g bars then just use any size Mars Bars as long as the total weight is approximately 190g.
- 80g unsalted butter, chopped, plus extra for greasing
- pinch of salt
- 110g Rice Bubbles, or Rice Krispies, or Rice Pops
Chocolate Topping
- 275g milk melting chocolate, note 1
- 1 tablespoon vegetable oil
Instructions
- Line a 20cm (8") square baking tin with baking paper and put aside.
- Chop the Mars Bars into 2 cm pieces and add them to the Thermomix bowl. Add the butter and pinch of salt and melt for 5 minutes/60°C/Speed 2.5. The Mars Bars will melt and the mixture will be thick. Please note - don't worry if the Mars Bars don't completely melt, it will still be okay. Scrape down the bowl with a spatula and give the mixture a good stir.
- Add the rice bubbles to the Thermomix and mix for 20 sec/reverse/speed 3 until combined. Scrape down the bowl with a spatula and give the mixture a good stir.
- Transfer the mixture to the tin and press down with the back of a spoon until smooth and leveled. Don't forget the corners!
- Place in the fridge to set whilst you make the chocolate topping.
For the Chocolate Topping
- Clean and dry the Thermomix bowl. Place the chocolate in the Thermomix bowl and grate for 8 sec/speed 10. Scrape down the bowl, add the vegetable oil then melt for 3 mins/50°/speed 2. Check that it's melted, if not, scrape down the bowl then melt again for a 1-2 mins/50°/speed 2.
- Pour the melted chocolate over the crackles, then smooth over the top with a spoon or pallete knife.
- Leave to set in the fridge for 2-3 hours or overnight.
To Serve
- Take the Mars Bar Slice out of the fridge 30 minutes before serving. Cut into squares or slices with a warm knife.
Notes
Note 1. Milk chocolate - use baking chocolate melts. Excellent quality brands are Cadburys or Nestle. I don't recommend home-brand baking chocolate for this recipe, as the taste is not good. Also, it's important not to use normal milk chocolate, as it won't set properly.
Nutrition Information:
Yield: 12 Serving Size: 1Amount Per Serving: Calories: 244Total Fat: 11gSaturated Fat: 5gTrans Fat: 0gUnsaturated Fat: 3gCholesterol: 16mgSodium: 129mgCarbohydrates: 34gFiber: 1gSugar: 17gProtein: 3g
The information shown is an estimate provided by an online nutrition calculator. It should not be considered a substitute for a professional nutritionist’s advice.
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