Preheat the oven to 180°C/gas mark 4. Butter two Victoria sponge cake tins and line the bottom of each with greaseproof paper

Using an electric whisk or a stand mixer, beat the caster sugar, soft brown sugar, eggs and vanilla together for about four minutes until creamy. Slowly add the vegetable oil and mix again well

Sift in the flour, cocoa powder, baking powder, bicarbonate of soda and stir together well with a metal spoon. Add a pinch of salt and stir in the plain yoghurt, mix well

Divide the mixture equally into the prepared baking tins and bake for 30 minutes, checking after 25 minutes to see whether a cocktail stick comes out clean. Once cooked, take the sponges out of the oven and leave to cool

To make the filling, beat the butter (at room temperature) until soft and a little fluffy. Carefully add the icing sugar a little at a time and keep mixing until the whole amount is added in. Add the caramel sauce and a pinch of sea salt and mix in well

Once the sponges are completely cool, carefully slice them in half across the middle so that you have four sponges. Put the first layer directly onto a serving plate or cake stand and spread one third of the butter cream over the sponge almost to the edge. Repeat until you have three layers and then place the final sponge on top

To make the chocolate fudge topping, melt the chocolate in a glass bowl over a pan of boiling water. Once melted, take off the heat and stir in the cream and the caramel. Leave to cool, before spreading the fudge topping over the top layer of the cake. Decorate with fudge pieces

You will have some chocolate fudge sauce left over, so either re-heat and drizzle over the cake to serve, or use as a dipping sauce for some fresh British strawberries