Mini Chocolate Birthday Cake

This adorable Mini Chocolate Birthday Cake is perfect for small but special celebrations! The mini cake features two chocolate sponge layers baked in 4-inch tins, decorated with chocolate fudge frosting and birthday sprinkles. It’s rich and indulgent in flavour, with a moist and fudgy texture. If you know of a chocolate fanatic with a birthday coming up, bake them this mini cake!

This recipe is part of my Mini Cake Recipe series, including these delicious Mini Lemon Drizzle Loaf Cakes. More mini cake recipes coming soon!

What size is this Mini Chocolate Birthday Cake?

This mini chocolate birthday cake is 4-inches wide and about 5-inches tall. Cut into quarters, it will easily serve four people, or why not place the whole cake on a plate in the centre of the table along with some forks for your guests to dig in. It’s just the right size for small birthday celebrations without excessive leftovers, or package the cake in a pretty box as a thoughtful gift. For this recipe you will need these 4-inch baking tins.

Ingredients To Make the Mini Chocolate Cake

Here’s a list of the ingredients you will need to make the chocolate sponges for your mini birthday cake:

• Golden caster sugar: Provides sweetness and helps to create a tender crumb. It also has a slight caramel flavour due to its molasses content, enhancing the overall taste of the cake. You can swap for white caster sugar if needed.
• Self-raising flour: Provides structure and rise to the cake due to the added raising agent. You can swap for 100g plain flour plus 1 teaspoon of baking powder.
• Cocoa powder: Essential for giving the mini chocolate cake its rich flavour. You a good-quality 100% cocoa powder for an intense flavour.
• Espresso powder (optional): Deepens the flavour of chocolate without making the cake taste like coffee. It’s a common trick used in baking to intensify the richness of chocolate desserts.
• Vegetable oil: Adds moisture and helps create a soft and tender sponge.
• Milk: Provides additional moisture and fat, contributing to the cake’s overall soft texture and rich flavour.
• Eggs: Provide structure, moisture, and richness. This recipe uses 2 medium room temperature eggs.
• Boiling water: Helps to “bloom” the cocoa powder, intensifying its flavour and ensuring it dissolves fully. It also creates a thinner batter, which results in a moister sponge.

Chocolate Fudge Frosting Recipe

This is the easiest and most delicious chocolate fudge frosting you’ll ever make! It’s made using just four ingredients (plus a pinch of salt to balance the sweetness); butter, dark chocolate, condensed milk and icing sugar. The result is a luxurious frosting with a melt-in-your-mouth velvety texture and a fudgy consistency. Ideal for spreading or piping onto cakes, cupcakes, brownies, and other desserts.

All the ingredients are measured into a saucepan and heated gently until smooth and glossy. Super simple and quick! It’s important not to overheat the ingredients otherwise the chocolate will start to separate and the frosting will turn oily. As soon as there are no visible lumps of chocolate, remove from the heat and pour into a shallow bowl. Let the frosting cool in the fridge for 30 minutes, then use to assemble the mini chocolate cake.

Mini Chocolate Birthday Cake

This adorable Mini Chocolate Birthday Cake is perfect for small but special celebrations! The mini cake features two chocolate sponge layers baked in 4-inch tins, decorated with chocolate fudge frosting and birthday sprinkles. It's rich and indulgent in flavour, with a moist and fudgy texture. If you know of a chocolate fanatic with a birthday coming up, bake them this mini cake!

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Prep: 45 minutes minutes

Cook: 35 minutes minutes

Total: 1 hour hour 15 minutes minutes

Servings: 4

Equipment

• 4-inch cake tins at least 2-inches tall

Ingredients

For the chocolate sponge:

• 125 grams Golden caster sugar
• 100 grams Self-raising flour
• 40 grams Cocoa powder
• 0.5 teaspoon Espresso powder optional, but helps bring out the chocolate flavour!
• 50 millilitres Vegetable oil
• 80 millilitres Milk
• 2 medium Eggs room temperature
• 1 tablespoon Boiling water

For the chocolate fudge frosting:

• 75 grams Unsalted butter
• 150 grams Dark chocolate
• 75 grams Icing sugar
• 200 grams Condensed milk
• Pinch Salt

Decorations:

• Sprinkles
• Birthday candles

Metric – US Customary

Instructions

Start by making the chocolate sponge cakes:

• Preheat the oven to 160°C fan / 180°C conventional. Grease and line the base and sides of two 4-inch round cake tins with greaseproof paper.
• In a medium-sized bowl, whisk the sugar, flour, cocoa powder and espresso powder (if using) together.
  125 grams Golden caster sugar, 100 grams Self-raising flour, 40 grams Cocoa powder, 0.5 teaspoon Espresso powder
• Whisk the vegetable oil, milk, and eggs in a separate bowl. Slowly whisk in the boiling water bit by bit, to avoid cooking the eggs.
  50 millilitres Vegetable oil, 80 millilitres Milk, 2 medium Eggs, 1 tablespoon Boiling water
• Pour the wet ingredients into the dry and whisk until smooth and combined. The mixture will be very thin.
• Divide the cake mixture evenly between the baking tins. Bake for 35-40 minutes until risen and the middle of the sponge springs back when lightly pressed. Leave to cool completely on a wire rack.

Make the chocolate fudge frosting:

• Measure all of the ingredients into a medium-sized saucepan and place over a very low heat.
  75 grams Unsalted butter, 150 grams Dark chocolate, 75 grams Icing sugar, 200 grams Condensed milk
  
• Stir continuously until the butter and chocolate melt and the frosting is smooth and glossy. It's important not to overheat the mixture otherwise the chocolate will start to separate and the frosting will turn oily. As soon as there are no visible lumps of chocolate, remove from the heat and pour into a shallow bowl.
  
• Cover the bowl with clingfilm, patting down the middle so the clingfilm touches the surface of the frosting (this stops it from drying out). Leave to cool for 30 minutes.
  

Assemble the mini cake:

• Unwrap the frosting and give it a good stir. If it appears grainy or split, stir in 2-3 teaspoons of cold milk or condensed milk to bring the frosting back to a smooth and glossy appearance.
• Use a knife to trim the domed top off the cakes so they have a flat and level top. I like to call the offcuts 'chef's samples' 😉
• Place one sponge layer on a cake stand and spread a thick layer of frosting on top. Sandwich with the other sponge layer and coat the top and sides of the cake with frosting.
  
• Use the leftover frosting to pipe swirls on top and decorate with birthday sprinkles.
  

Video

Notes

Store in a baking tin at room temperature for up to 4 days.