In a bowl, vigorously beat the eggs and the melted butter.
Add the crème fraîche and the flour in a steady stream while continually stirring to avoid the formation of lumps.
Cut the Reblochon into small pieces with its rind still on, and add it to the mixture.
Season with salt and cracked black pepper.
Preheat the oven to 180° thermostat 6. Grease and flour an ovenproof dish.
Pour in the mixture, then add the Mirabelle plums.
Cook the clafoutis for 40 minutes.
Leave to cool and then dust with icing sugar before serving.
The clafoutis can be enjoyed at any time of the day.
It's also delicious served warm with a salad of crunchy baby lettuce leaves seasoned with nut oil, only after the meal during the cheese course.