1. Rehydrate the dried morels for 15 minutes in warm water. After 15 minutes, drain them. Then place them in a saucepan filled with boiling water and leave them for 1 minute from when the water returns to the boil, then drain them again. Set aside.
2. Cut the fillet steak into 2.5 cm slices and season lightly with salt. Sear them over a high heat in butter until golden brown, then continue cooking for 1 to 2 minutes over a low heat.
3. Keep warm in an oven at 90°C.
4. In the same pan, sauté the chopped shallot for 1 minute, add the morels and cook for another minute.
5. Pour the Cognac and veal stock into the pan, reduce for 2 to 3 minutes, then add the single cream and allow to thicken until the desired consistency is achieved.
6. Place the filet mignon medallions in a dish and coat them with the morel sauce.

Non-alcoholic variation: you can replace the Cognac with veal stock, increasing the quantity.