1 Preheat the oven to 180 °C (th 6). Reserve 20 beautiful walnut kernels, mix the rest with the Saint-Michel cakes. Dilute the coffee in 2 tablespoons of water.
2 Separate the whites from the yolks, whisk the yolks with the sugar until the mixture whitens. Add the nut/cake mixture, coffee and butter. Mix perfectly.
3 Whisk the egg whites until stiff, add them to the mixture. Pour into small silicone moulds slightly moistened. Place a walnut kernel on top of each one. Bake for about 20 minutes. Turn out and serve cold.