Decadent and moist chocolate cupcakes with Mars bars title
Cakes & biscuits,  Yum

Decadent and moist chocolate cupcakes with Mars bars

I don’t know where I originally found the recipe for these decadent and moist chocolate cupcakes. It has been in my recipe journal for so long and used so often, that it has bits of cocoa and something sticky on the page. Yet this recipe has never let me down.

This decadent and moist chocolate cupcake recipe is one of my go-to recipes – unless I am making cupcakes for friends with allergies. I have a number of recipes in my wheelhouse that I have tried and used on numerous occasions and know they will turn out. This recipe is particularly good because I can easily adjust the topping or filling to suit.

They are even great on their own!



If you add the Mars bar to the cupcake pans before adding the batter, the Mars bar tends to overcook and go hard at the bottom of the cupcake. While it still tastes fine, the consistency is not as pleasant. It is better to immerse the Mars bar in the batter after you have poured the batter into the cupcake pans.

If you normally test whether your cakes are cooked by inserting a tester, make sure you check twice. You might get inconsistent readings if you hit the bit of Mars bar during your test.

The cupcakes will remain moist for a number of days. However, when you apply frosting, they should be kept cool and in an air-tight container and eaten within two days.


Don’t walk away from your syrup! It feels like it takes ages for the syrup to take on any colour, then it goes from 0 to 100 in a very short period of time and starts to burn.

If using, make your syrup before or while the cupcakes are baking, so that it has enough time to cool. If time is short, use good-quality store bought caramel sauce.


Don’t bother washing your frosting bowl, beaters, spatulas, etc. until you have iced your first couple of cupcakes. Sometimes the mixture will need a little more icing sugar or cocoa or cream to give it the right consistency. If you are adding icing sugar, add a little cocoa too, otherwise the frosting will just be too sweet.

Variations on a theme

I have made so many variations for it over the years. For example:

  • White chocolate frosting and a chocolate mousse filling.
  • Themed cupcakes, with frosting and decorations to suit the themes. One memorable batch had grey frosting and fondant light sabres in red, blue and green and edible glitter for a Star Wars part.
  • ‘Brain’ cupcakes with raspberry and white chocolate frosting piped to look like a brain
  • Sacher torte cupcakes
  • Chocolate and raspberry cupcakes with raspberry filling and white chocolate and raspberry frosting.

These decadent and moist chocolate cupcakes really are that versatile!

Of course, you don’t have to use Mars bars. You could use almost any chocolate bar of your choice! I wouldn’t suggest that you use a biscuit-based chocolate bar in the cupcake, though as the consistency wouldn’t work.

Decadent and moist chocolate cupcakes with Mars Bar - banner
Decadent and moist chocolate cupcakes with Mars bars

Prep Time: 1 hour, 20 minutes

Cook Time: 35 minutes

1 hour, 55 minutes



Servings: 24 cupcakes

Decadent and moist chocolate Mars cupcakes

These delicious and moist chocolate cupcakes have never let me down. They are easy to make and are always quick to disappear. They are so versatile!


  • 1 3/3 cups plain flour
  • 2 cups of white sugar
  • 3/4 cup of unsweetened cocoa powder
  • 1 1/2 tsp. bicarbonate of soda (baking soda)
  • 3/4 tsp. salt
  • 2 large eggs
  • 1 cup of buttermilk (or 1 tbsp of white vinegar mixed into a cup of milk)
  • 1/2 cup of butter, melted
  • 1 tbsp. vanilla sugar (or vanilla extract)
  • 1 cup of hot coffee (instant, filter or diluted espresso)
  • 12 mini Mars bars, halved lengthwise (optional)
    Caramel (filling or drizzle)
  • 1 cup white sugar
  • 1/4 cup water
  • 2 tbsp. butter
  • 3/4 cup heavy cream
  • 1 tsp vanilla sugar (vanilla extract)
  • 1 pinch of salt
  • 250 g butter at room temperature
  • 2 cups of icing sugar
  • 5 tbsp unsweetened cocoa powder
  • 2 tbsp. cream
  • a pinch of salt
  • 1/2 tsp. vanilla sugar or vanilla essence.
  • 1-2 packets of Mars bites (optional). Halve each ‘bite’.


  1. Preheat the oven to 190°c. Place paper cupcake pans in the cupcake form.
  2. Sift the flour, cocoa, baking soda and salt into a bowl. Add the sugar and stir well.
  3. Add the eggs, buttermilk, melted butter and vanilla and beat until smooth. The mixture will be quite thick.
  4. Pour in the coffee and stir in carefully with a spatula until the texture of the batter is even. It will be quite runny.
  5. Fill the cupcake pans with batter until they are two-thirds full. If you are adding Mars bar, push half of a mini Mars bar into each cupcake pan until it is just covered in batter.
  6. Bake for 20-24 minutes. Allow to cool before frosting.
  1. Add sugar and water to a saucepan. Place over medium heat and wait for the sugar to dissolve.
  2. Once the sugar has dissolved (looks like a clear syrup), turn the heat up to medium-high and cook until the syrup turns a nice amber colour.
  3. When you like the colour, add the butter, stirring well. The caramel will start to froth up and bubble. Remove from heat.
  4. Add the cream and stir to combine, then add the vanilla and salt and stir well.
  5. Allow to cool. The caramel sauce will thicken significantly as it cools.
  6. Once the caramel has cooled, used it as filling in the cupcakes or drizzle over the top. To use as filling: use a spoon to cut a hat off the cupcake, add a good spoon of caramel to the hole and replace the hat. Frost over the hole to disguise.
  1. Whip the butter until it is light and fluffy. I use the paddle attachment on my KitchenAid.
  2. Sift in the icing sugar and cocoa powder (to remove lumps) and mix well.
  3. Add the salt, vanilla and the cream little-by-little until the right consistency is reached.
  4. Pipe onto cooled cupcakes. Top with the Mars bites and drizzle with caramel sauce, as desired.


Enjoy customising them!
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