Grate parmesan. Mix eggs, cream and crème fraiche with the whisk of the hand mixer. Season well with salt, pepper and nutmeg. Stir in 75 g parmesan. Cut bread into slices.
Brush thinly with butter. Put them in a greased ovenproof dish and pour the Parmesan and egg cream over them. Let it rest for about 15 minutes. Sprinkle with 25 g Parmesan and bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 45-50 minutes. Remove from the oven and serve garnished with basil