Mosaic Cake

1. Prepare the Biscuits and Walnuts

Break 200 grams of digestive biscuits into bite-sized chunks. Don’t make the biscuits too small.

Chop 50 grams of walnuts and lightly toast them in a dry frying pan for extra flavour. Once toasted, let them cool.

2. Make the Chocolate Mixture

In a small saucepan, combine 120 grams of unsalted butter, 90 grams of caster sugar, 1½ tablespoons of unsweetened cocoa powder, and 120 millilitres of milk.

Heat the mixture over medium-low and stir until smooth and completely melted.

Remove the saucepan from heat and stir in 150 grams of chopped chocolate until melted. Finally, add 1 teaspoon of vanilla extract if using.

3. Combine

In a large mixing bowl, mix the biscuit pieces and walnuts.

Pour the warm chocolate mixture over them and stir until everything is well coated.

4. Shape and Chill

Transfer the mixture to a 20 cm (8”) diameter baking tin lined with baking parchment. Press firmly to remove air gaps and create a flat surface.

Cover and chill in the refrigerator for at least 4 hours or until firm (overnight is best).

5. Prepare the Frosting

Chop 100 grams of dark chocolate and place it in a bowl.

Heat 60 millilitres of double cream in a small saucepan or microwave until just starting to simmer (don’t boil).

Pour the hot cream over the chocolate. Let it sit for 1 minute, then stir slowly until smooth.

Stir in 15 grams of unsalted butter and 1 teaspoon of vanilla extract (if using). Let the frosting cool slightly.

6. Assemble the Cake

Remove the mosaic cake from the tin.

Using a spatula, gently spread the chocolate frosting over the cooled cake.

Chill for 15-20 minutes before slicing to allow the frosting to set.

7. Serve

For a nice finishing touch, sprinkle with chopped walnuts or crushed biscuits.

Slice the mosaic cake and serve cold.

Tips for the Perfect Mosaic Cake

To ensure that your cake turns out really well, here are a few tips:

Good Quality Chocolate: Use good quality chocolate for the cake. The better the chocolate, the better your Mosaik Cake will be!

Don’t Crush the Biscuits Too Much: For the classic mosaic look, you need bite-sized chunks, not crumbs.

Line the Tin Well: Use cling film or baking parchment, so the cake can be easily removed.

Press the Mixture Firmly: This will help the cake keep its shape and cut cleanly.

Variations to Try

Mosaic cake is super flexible, so you can customize it in all sorts of ways. Here are some tasty variations to inspire you:

Nutty Twist: Add a spoonful of nut butter (peanut, hazelnut, etc.) to the chocolate mixture to make it richer.

Fruity Note: Add dried cherries, raisins, or chopped dried apricots for contrast.

Coffee Vibes: Stir 1 teaspoon of instant espresso powder into the chocolate mixture.

Spice It Up: For a subtle kick, add a pinch of cinnamon, nutmeg, or even chilli powder.

Storage Tips

In the Fridge: Store the cake in an airtight container in the refrigerator. It will keep well for 5–6 days. The chocolate frosting stays glossy, and the biscuits keep their nice texture.

In the Freezer: You can also freeze it (whole or sliced). Wrap tightly in plastic wrap and then place in a freezer-safe container or bag. It lasts up to 2 months.

To serve, thaw in the refrigerator overnight.

Serving Tip: For the best texture, especially with the frosting topping, take it out of the fridge 10-15 minutes before serving to allow it to soften slightly.

For more sweet indulgence, check out these delicious recipes:

No-Bake Chocolate Biscuit Cake

No-Bake Cake with Ermine Filling

No-Bake Chocolate Peanut Butter Bars

Conclusion

Whether you serve this mosaic cake to your guests or sneak a slice straight from the fridge, this chocolaty, crunchy classic is the kind of treat that makes any day special.