Melt the chocolate in a bowl over hot water. Leave to cool slightly.
Cream the butter and sugar until light and fluffy, then beat in the chocolate followed by the eggs.
Sift in the dry ingredients, then stir gently in alternating with the yogurt and a couple of tbsp of water.
Fold in the meringue pieces from two of the nests.
Divide the mixture between two 20 cm (8″) round cake moulds and bake at 180℃ for 30 minutes when the cakes should be well risen and a skewer inserted into the centre comes out clean. Leave in the moulds to cool for a few minutes then turn out onto a wire rack to cool completely.
Whip the cream with chosen cordial until peaks form. Divide the mixture into two. Put one aside and add half of the strawberries to the other along with a couple of the crushed meringue nests.
Sandwich the two cakes with the Eton Mess. Spread the remaining cream over the top, then scatter over the remaining strawberries followed by the remaining crushed meringue pieces.
Serve immediately before the meringue has a chance to go soft.