Mary Berry Mars Bar Cake Recipe

Mary Berry Mars Bar cake is a rich, no-bake chocolate treat made with melted Mars bars, butter, and crunchy biscuits, then finished with a smooth chocolate topping. It is sweet, indulgent, and wonderfully nostalgic, making it perfect for parties, bake sales, or an easy fridge cake when you want a fuss-free dessert. This recipe uses a simple no-bake method and comes together quickly with minimal equipment.

What Is Mary Berry Mars Bar Cake?

Mary Berry Mars Bar cake is a classic British fridge cake where chopped Mars bars are melted with butter to create a sticky caramel-chocolate base. Crushed biscuits are folded in for texture, and the mixture is set in the fridge before being topped with melted chocolate. The result is a sliceable cake that is chewy, crunchy, and chocolatey all at once.

Other Popular Mary Berry Recipes

• Mary Berry Turkey Crown Gravy
• Mary Berry Fragrant Chicken Traybake

Why This Recipe Is Worth Trying

• No baking required – Ideal when you want a quick dessert
• Rich chocolate flavour – Mars bars add caramel sweetness
• Beginner-friendly – Very hard to go wrong
• Great for sharing – Easy to cut into neat slices
• Perfect make-ahead treat – Sets well in the fridge

Essential Ingredients to Make Mary Berry Mars Bar Cake

• Mars bars – 6 standard bars (about 230 g), chopped
• Unsalted butter – 100 g
• Digestive biscuits – 200 g, roughly crushed
• Milk chocolate – 200 g, broken into pieces

Handy Kitchen Tools for Best Results

• Saucepan
• Heatproof bowl (optional)
• Wooden spoon
• 20 cm square tin
• Baking parchment

Step-by-Step Guide to Making Mary Berry Mars Bar Cake

• Prepare the tin – Line the base and sides of the tin with baking parchment.
• Melt Mars bars and butter – Place the chopped Mars bars and butter in a saucepan over low heat, stirring gently until completely melted and smooth.
• Crush the biscuits – Break the digestives into chunky crumbs, keeping some texture.
• Combine the mixture – Remove the pan from the heat and stir in the crushed biscuits until evenly coated.
• Press into the tin – Spoon the mixture into the prepared tin and press down firmly with the back of a spoon.
• Melt the chocolate topping – Melt the milk chocolate gently over low heat or in short microwave bursts.
• Add the topping – Pour the melted chocolate over the biscuit base and spread evenly.
• Chill to set – Refrigerate for at least 2 hours, or until firm.
• Slice and serve – Cut into squares using a warm knife for neat edges.

What I Got Wrong (And How I Fixed It)

• Base too crumbly – Pressing the mixture more firmly fixed this.
• Chocolate topping cracked – Letting it soften slightly before slicing helped.
• Overheating Mars bars – Using low heat prevented splitting.
• Uneven slices – Warming the knife made cleaner cuts.

Healthier Version of Mary Berry Mars Bar Cake

• Smaller portions – Cut into bite-sized squares
• Dark chocolate topping – Reduces sweetness slightly
• Reduced butter – Use 80 g instead of 100 g
• Add nuts – Improves texture and balance

Ingredient Substitutions for Mary Berry Mars Bar Cake

• Digestive biscuits – Rich tea or graham crackers
• Milk chocolate – Dark or half-and-half chocolate
• Mars bars – Caramel chocolate bars with nougat
• Butter – Dairy-free baking spread

Pairing Ideas: What to Serve With Mary Berry Mars Bar Cake

• Hot tea or coffee – Cuts through the sweetness
• Vanilla ice cream – Turns it into a plated dessert
• Fresh berries – Adds contrast
• Dessert platters – Great alongside other fridge cakes

Expert Tips to Make Perfect Mary Berry Mars Bar Cake

• Use low heat – Prevents the caramel from burning
• Keep biscuit chunks uneven – Better texture
• Line the tin well – Makes removal easy
• Press firmly – Ensures the base holds together
• Chill fully before slicing – Cleaner cuts
• Store chilled – Best texture when cold

Creative Ways to Customize Mary Berry Mars Bar Cake

• Crispy cereal addition – Replace some biscuits
• Nutty crunch – Add chopped peanuts
• White chocolate drizzle – Decorative finish
• Salted twist – Light sprinkle of sea salt on top

Storing Mary Berry Mars Bar Cake the Right Way

• Refrigerate – Store in an airtight container for up to 5 days
• Layer with parchment – Prevents sticking
• Freeze portions – Freeze slices for up to 1 month
• Defrost slowly – Best texture when thawed in the fridge

How to Reheat Mary Berry Mars Bar Cake (If Needed)

Reheating is not needed. Serve chilled or allow to sit at room temperature for 10 minutes if you prefer a softer bite.

Nutritional Breakdown (Per Serving)

• Calories: ~320 kcal
• Carbohydrates: ~38 g
• Fat: ~18 g
• Protein: ~3 g
• Sugar: ~25 g

Print

FAQs

Can I make Mars Bar cake without baking?

Yes, Mars Bar cake is a no-bake recipe. The base is made by melting Mars Bars with butter and mixing them with cereal, then setting it in the fridge rather than baking in the oven.

Why is my Mars Bar cake not setting properly?

This usually happens if the mixture is still warm when pressed into the tin or if there is too much butter. Chilling the cake for at least 2–3 hours allows it to firm up fully.

How do I stop Mars Bar cake from being too hard?

Overcooking the Mars Bars and butter can make the cake hard once set. Melt the mixture gently over low heat and remove it as soon as it is smooth.

Can I add chocolate on top of Mars Bar cake?

Yes, a chocolate topping is very common. Pour melted milk or dark chocolate over the base once it has cooled slightly, then chill again until set.

Wrapping It Up

Mary Berry Mars Bar cake is a simple, crowd-pleasing no-bake dessert that delivers big flavour with very little effort. Sweet, chewy, and chocolatey, it is the kind of treat that disappears quickly and is always requested again.