Nigella Mars Bar Cake

The first time I made this cake, I was half-hungover and dangerously low on willpower. It was a Sunday, and the rain hadn’t stopped since Friday. I had no energy for real baking, but I did have a pack of Mars Bars, some leftover Rice Krispies, and that one stubborn tin of golden syrup that never runs out. And honestly? That was enough.

This Mars Bar Cake is pure childhood nostalgia wrapped in adult-level indulgence. It’s squishy, crunchy, sweet in all the right ways, and requires zero oven time. You just melt, mix, pour, and chill — like a treat that practically makes itself while you hide under a blanket and wait for the kettle to boil.

Why You’ll Love It

• No-bake magic — perfect when turning on the oven feels like too much.
• You can’t mess it up — honestly, unless you forget it in the fridge for a week.
• Crowd-pleaser — kids and adults go mad for it.
• Ridiculously good with a cup of tea (or coffee… or a sneaky Bailey’s).
• Keeps well, freezes great — if it lasts long enough to store.
• Easily dressed up — add nuts, sea salt, or even a layer of caramel if you’re feeling flashy.

Ingredients

• 6 Mars Bars (chopped roughly)
• 150g unsalted butter
• 2 tbsp golden syrup
• 200g digestive biscuits (crushed into crumbs and chunks)
• 100g Rice Krispies
• 300g milk chocolate (for topping)

How to Make It

Get the gooey base going:

In a large saucepan, melt the butter and golden syrup over low heat. Stir gently — you don’t want it to boil. It should look glossy and slightly dangerous (in the best way).

Crush and crumble:

While the butter’s doing its thing, smash the digestives in a big bowl. I like a mix of crumbs and little biscuit boulders — better texture.

Stir in the crunch:

Once the butter mix is melted, stir in the Rice Krispies and crushed biscuits. Mix well so everything’s coated in sticky gold.

Chuck in the Mars Bars:

Add your chopped Mars Bars and fold them through while the mixture is still warm. Don’t fully melt them — you want gooey pockets of caramel here and there.

Press it down:

Line a square tin with baking paper. Press the mixture in — get it even and a little compact. Use the back of a spoon or your hands (sticky, but satisfying).

Get melty with chocolate:

Melt the milk chocolate gently — either in the microwave (30 sec bursts, stirring in between) or over a double boiler. Pour over the base and smooth it out.

Chill, then slice:

Pop the tray in the fridge for at least 2 hours. Once the top is set and it’s firm, lift it out and slice into squares. Or bars. Or wonky wedges. No judgment.

Common Mistakes and How to Dodge Them

Why is it falling apart when I slice it?
You probably didn’t press it down firmly enough before chilling. Give it a bit of muscle next time.

My Mars Bars melted into nothing!
Add them after everything else is mixed. Stir gently so you keep those chewy little nuggets of joy.

Chocolate top cracked when slicing!
Use a hot knife (just run it under hot water and dry it off). Makes a world of difference.

Too sweet?
Try a darker chocolate on top or add a pinch of sea salt to balance it out.

Storage and Reheating

Fridge:
Keeps happily in a sealed container for 3–4 days. Any longer and it starts to get… nostalgic.

Freezer:
Wrap slices individually and freeze for up to 3 months. Just thaw in the fridge overnight or eat it frozen like a rebel.

Microwave (for soft gooeyness):
10–15 seconds max — don’t go overboard or the chocolate will melt everywhere. Ask me how I know.

Frequently Asked Questions

Can I use a different chocolate bar?
Totally. Snickers works great. Or Crunchies. Or literally whatever’s hiding in the cupboard.

What if I don’t have golden syrup?
You can sub in honey or light corn syrup — just note it’ll taste slightly different (still good though).

Can I make this vegan?
Yep! Use vegan butter, dairy-free chocolate, and swap Mars Bars for a vegan caramel chocolate bar. It won’t be the same, but it’ll still be tasty.

How do I make it look fancy?
Drizzle with white chocolate. Sprinkle with chopped nuts. Pretend you bought it from a bakery.

Nutrition Facts (Per Serving)

• Calories: 400
• Fat: 20g
• Saturated Fat: 10g
• Carbs: 50g
• Sugars: 35g
• Protein: 5g
• Sodium: 100mg
• Fibre: 2g