Cut the truffles into 2 mm thick slices. Put a knob of butter in a sauté pan, fry for 3 minutes on each side, seasoning them with salt and pepper, and set them aside on a cloth.
Discard the cooking butter, deglaze with the sherry vinegar, reduce to ice. Add the Cassis wine. Let reduce by a third. Book. Glaze the top of each puff pastry using a small brush dipped in beaten egg, place them on a baking sheet and bake them in a hot oven at th.6 (200°C) for about fifteen minutes. Book.
Scallop the raw foie gras, season it with salt and pepper on each side. Put a nonstick skillet on the heat; when it is hot, sear the foie gras escalopes for 3 minutes on each side, remove and pat them dry between sheets of paper towel. Book.
Open the puff pastries, remove the hats and place the slices of foie gras in the bases, alternating them with the slices of truffles.
Put the sauce back on low heat, add the cream. Pass the puff pastry bases filled with their tops, place on a dish, in a low oven (th.2) 3 minutes.
Meanwhile, add the rest of the butter to the sauce, give the pan a gyratory motion until the butter is well incorporated into the sauce, salt and taste.
Remove the puff pastries from the oven, remove the caps and cover with the sauce, sprinkle with chopped chervil and cover them with their caps. Serve immediately.
My advice:If you don't have a white Cassis wine, use a white Graves. If, by any chance, when you taste the sauce, it was a bit acidic, add a very light pinch of caster sugar.
Joëlle's point of view:It's a rich and expensive dish. For this reason, I asked the chef to reduce the proportions to two people. Make sure the liver is hot inside to check, press with your index finger in the center of the slice, it must be hot otherwise continue cooking a little.
Suggested wine:White wine from Cassis (Clos-Sainte-Magdeleine).
