Preheat the oven to 180°C (350°F) Gas 4.

Put the chocolate in a heatproof bowl set over a pan of gently simmering water. Do not let the bowl touch the water. Leave until almost melted. Remove from the heat.

Beat together the butter and sugar until pale and creamy, then beat in the eggs, one at a time. Stir in the crème fraîche, then sift the flour into the mixture and fold in. Stir in the melted chocolate, followed by the Grand Marnier.

Spoon the mixture into the paper cases and bake in the preheated oven for 18 minutes until risen and a skewer inserted in the centre comes out clean. Transfer to a wire rack to cool.

To decorate, gently heat the cream until almost boiling, then pour over the chopped chocolate and leave to melt for about 5 minutes. Stir until the chocolate has melted, then refrigerate for 20–30 minutes. Beat until thick and glossy, then spoon on top of the cakes.Top each cake with a perfect rose petal to serve.