For sponge (you will need a baking tray measuring approx 30cm x 23cm)

Brush the tray lightly with vegetable oil, cut a sheet of baking parchment slightly bigger than the tray, at each corner make a 2-inch cut diagonally in towards the centre of the paper. This forms corners when placed in the tray

1.Melt the 5oz/150g of chocolate in a heatproof bowl over and saucepan with hot water in it (make sure the water does not touch the end of the bowl).

2.Separate the eggs into two bowls.

3.Add the sugar into the egg yolks, whisk this with a hand whisk for 3to 4 minutes.

4.Meanwhile with an electric mixer beat the egg whites until stiff and will hold a peak

5.Take the chocolate off from saucepan of water when melted, allow to cool for 2 mins and then scrape the chocolate into the egg yolks and sugar, stir this together with a large metal spoon until totally combined.

6.Add a ¼ of the beaten egg whites into the chocolate mixture, fold it through gently using the large metal spoon. Gradually add the remaining beaten egg whites in batches, until all incorporated.

7.Spread onto the lined baking tray and cook for 20 minutes. When cooked, take from the oven, and allow to cool for 10 minutes

8.Lay a clean piece of parchment out on the counter sprinkle with a small amount of caster sugar Turn the baking tray upside down onto the parchment, the sponge will now have the oiled parchment facing upwards. Remove this gently

9.Cut the sponge into two halves to form two rectangles.

You will need a roasting tray or dish the size of the rectangles you have cut to assemble the dessert. Brush the tray or dish with vegetable oil and layer cling film into and over the sides of the dish, making sure to press it into the corners.

Put one rectangle of sponge onto the clingfilm lined tray to form the base

Make the filling

1.      Melt the 12oz/360g of chocolate and the butter in a heatproof bowl over and saucepan with hot water in it (make sure the water does not touch the end of the bowl).

2.      Whip the cream in a clean bowl until it is stiff

3.      When the chocolate is fully melted, take off the heat and stir the mixture so the butter and chocolate are combined well.

4.      Take a large metal spoon and fold in a spoonful of the whipped cream into the chocolate mixture, gradually add the remainder of the cream.

5.      Sprinkle half of the frozen raspberries onto the sponge base

6.      Fill half of the cream and chocolate mixture on top, then more raspberries

7.      Top this with the remainder of the cream and chocolate mixture, finally, place the other rectangle of sponge on top and press it down gently, refrigerate for 2 hours and then cover and freeze until Christmas.