The first time I made this, I was halfway through mixing when I realised my sugar thermometer had vanished into the drawer of doom. Cue frantic Googling and the discovery of the “instant” version of American frosting. And to be honest? It saved the bake—and my nerves.

This cake is everything a proper Devil’s Food Cake should be: deep, dark cocoa flavour, soft crumb, and that perfect slightly bitter edge that keeps it from being sickly. The frosting is what takes it from good to “hide a slice for yourself before it disappears” level. It sets into a glossy, meringue-like shell that crackles under your fork but is pillowy inside.

Whether you go full sugar syrup or use the shortcut version, this one’s a keeper. It’s got that old-school bakery vibe but still feels modern enough for any birthday table.

WHY THIS ONE WORKS SO WELL

Cocoa + bicarb = deep chocolate punch – Without being too sweet.
Boiled water makes the cocoa bloom – It intensifies the flavour, don’t skip it.
Frosting sets like a dream – Crisp top, marshmallow centre.

INGREDIENTS + WHY THEY MATTER

Cocoa powder (50g) – Choose a rich, unsweetened cocoa. This is where the chocolate flavour lives.
Boiling water (225ml) – Helps bloom the cocoa for a deeper taste.
Soft margarine (100g) – Keeps the sponge extra soft.
Caster sugar (275g) – Balances the bitterness and helps with structure.
Bicarb + baking powder – Essential combo for rise and lightness.
Plain flour (175g) – Keeps it tender and fine-crumbed.
American frosting – Just egg whites, sugar, and water. No butter, all fluff.

WANT TO CHANGE IT UP? HERE’S HOW

Frosting alternative – Swap for chocolate ganache or whipped cream if you’re not in the mood to boil sugar.
Make it boozy – Add a tablespoon of coffee liqueur to the cake batter. Deepens the chocolate even more.
Cupcake version? Absolutely. Bake for 18–20 minutes at the same temp.

MISTAKES I’VE MADE (AND HOW TO AVOID THEM)

WHAT WENT WRONG	WHY IT HAPPENS	HOW TO FIX IT
Cake too dry	Overbaked or cocoa not bloomed	Check at 30 mins and bloom the cocoa
Frosting too runny	Didn’t whip long enough	Whisk until it starts to look matte
Frosting set too fast	Waited too long to use it	Work quickly once it’s ready

HOW TO MAKE MARY BERRY’S DEVIL’S FOOD CAKE

PREHEAT + PREP
Preheat oven to 180°C/350°F/Gas 4. Grease and line two 20cm sandwich tins with baking paper.

MAKE COCOA MIX
Whisk 50g cocoa powder with 225ml boiling water until smooth. Set aside to cool slightly.

CREAM BUTTER + SUGAR
Beat 100g margarine and 275g caster sugar until pale and fluffy. Lightly whisk 2 eggs, then gradually add to the mix.

FOLD IN DRY + WET
Sift together 175g plain flour, ¼ tsp baking powder, and 1 tsp bicarb. Fold into the butter mix, alternating with the cocoa mixture.

BAKE
Divide between tins. Bake for 30–35 minutes or until a skewer comes out clean. Cool in tins for 5 minutes, then on a wire rack.

MAKE AMERICAN FROSTING
In a pan, heat 450g sugar with 135ml water until it reaches 115°C (soft ball stage). Meanwhile, whisk 2 egg whites to stiff peaks. Slowly pour syrup into whites while whisking. Continue whisking until thick, glossy, and slightly matte at the edges.

ASSEMBLE
Spread a little frosting on one cake. Top with second layer. Use the rest to frost top and sides, creating soft peaks with a palette knife. Leave to set.

QUICK FROSTING OPTION (NO THERMOMETER)
Whisk 2 egg whites with ½ tsp cream of tartar to soft peaks. Gradually add 200g icing sugar and 1 tsp vanilla. Whisk until thick and glossy. Use immediately.

TIPS FROM MY KITCHEN

Don’t let the frosting sit—it sets fast. Keep your palette knife ready.
If the sugar syrup goes over 115°C, it’ll start to crystallise. Keep an eye on it.
Let the cakes cool completely before frosting or the topping will melt and slide.

STORAGE + SERVING

Room temp: Keeps up to 3 days in an airtight tin.
Fridge: Can refrigerate for up to 5 days—but bring to room temp before serving.
Freezer: Freeze unfrosted layers for up to 3 months. Wrap tightly.

FREQUENTLY ASKED QUESTIONS

Q: Can I use butter instead of margarine?
A: Absolutely. Just make sure it’s softened so it creams well.

Q: Do I need a sugar thermometer?
A: It helps, but if you don’t have one, use the instant frosting method—it’s easier and still fluffy.

Q: Can I make this gluten-free?
A: Yes—swap for a 1:1 GF flour blend and add ½ tsp xanthan gum if needed.

Try More Recipes:

Devil’S Food Cake (Inspired By Mary Berry)

Course: CakesCuisine: BritishDifficulty: Easy

Servings

servings

Prep time

minutes

Cooking time

minutes

Calories

300

kcal

A dark, cocoa-rich sponge with just enough bitterness to balance the fluffy American frosting. Perfect for chocolate lovers who like a little drama in their dessert.

Ingredients

For the Cake:
50g cocoa powder
225ml boiling water
100g soft margarine
275g caster sugar
2 eggs
175g plain flour
¼ tsp baking powder
1 tsp bicarbonate of soda
For the American Frosting:
450g caster sugar
135ml water
2 egg whites
Quick Version:
2 egg whites
½ tsp cream of tartar
200g icing sugar
1 tsp vanilla extract

Directions

Preheat oven to 180°C. Grease and line two 20cm sandwich tins.
Mix cocoa with boiling water until smooth. Set aside.
Cream margarine and sugar until pale. Add eggs gradually.
Sift flour, baking powder, and bicarb. Fold into batter, alternating with cocoa mixture.
Divide between tins and bake for 30–35 minutes. Cool on rack.
For frosting, boil sugar + water to 115°C. Whip egg whites to peaks. Pour syrup in slowly while whisking. Whisk until fluffy and glossy.
Assemble and frost cake quickly before it sets.

Notes

Use room temp ingredients for smooth batter.
The frosting is best made fresh and used straight away.
You can flavour the frosting with vanilla, almond, or even orange extract.