Preheat the oven to 180°C/160°C fan/Gas 4, then grease the tins with baking spread and line the bases with baking paper.

Sift the cocoa powder into a large bowl. Pour in the boiling water and stir into a smooth paste. Add the remaining ingredients and beat together using an electric hand whisk until light and fluffy. Spoon into the prepared tins and level the tops.

Bake the cakes in the oven for 20-25 minutes (ideally on the same shelf, so that they cook at the same rate) until well risen and coming away from the sides of the tins. Transfer to a wire rack to cool for 10 minutes, then remove the baking paper and leave to cool down completely.

To make the icing, soak the gelatine leaves in a bowl of cold water for 5 minutes until soft. Measure the sugar, cocoa powder and cream into a saucepan and pour in 125ml (4fl oz) of water. Stir the mixture over a gentle heat until the sugar has dissolved, then bring to the boil and continue to stir until smooth.

Remove from the heat and add the chocolate pieces to the hot liquid, allowing them to melt. Leave to cool for 5 minutes. Remove the gelatine leaves from the bowl of water and squeeze out any liquid before adding to the pan. Stir the warm chocolate mixture until the gelatine has dissolved, then pour through a sieve into a bowl. Place in the fridge to cool down forabout an hour and thicken to the consistency of thick mayonnaise.

Slice each sponge in half horizontally. Spread a third of the whipped cream over one layer of sponge, followed by another layer of cream and sponge, and continue to assemble the cake until you have four layers of sponge and three of cream. Press the sponges down between each layer so the cream comes right to the edges and the sponges are level at the sides.Take a palette knife and smooth around the edges so the excess cream very lightly covers the sides and gives a smooth edge.

Warm the apricot jam in a small saucepan and then pour through a sieve to remove any lumps. Brush the warmed jam over the top the cake (see tip), then chill in the fridge for 15 minutes.

Pour 50ml (2fl oz) of the icing into a bowl, then dip the top half of each strawberry into the melted icing and set aside on baking paper to set.

Pour or spoon the remaining icing over the top of the cake, smoothing it over the top and sides with a palette knife. Be very careful doing this - you want a smooth shiny icing (see tip). Leave for an hour or so to set.

Arrange the chocolate-iced strawberries around the bottom edge of the cake to serve.

Cook time: 25-30 minutes, plus cooling

PREPARE AHEAD The cake can be fully made and iced up to a day ahead and kept in the fridge.

FREEZE The sponges freeze well.

MARYS EVERYDAY TIPS Leaf gelatine comes in various sizes now so it is best to check it by weight.The apricot jam seals the cake and any loose crumbs, so that the icing has a smooth surface to cover.

When icing the cake, use long slow strokes with your palette knife to give the best finish. If a stray crumb gets on the palette knife, wipe it off with kitchen paper before retouching the cake. And if the chilled chocolate icing has thickened too much on sitting, give it a good beat with a spoon at room temperature to loosen it up again.