Soak the dry boletus mushroom in 2000 ml of cold water for 15 minutes. Drain the mushrooms and also save the water they were soaking in. Cut the shallot and fennel into thin slices. Cut the white part of the leek into ½ cm slices.
Heat the olive oil in a pot, add the sliced vegetables, braise shortly and pour in the water the mushrooms were soaked in.
Keep cooking until all the liquid evaporates. Then add cognac, chicken stock, cream and the soaked mushrooms. Let it cook at medium heat for approximately 20 minutes. Then place it into a glass jug stand blender and finely blend. Strain the soup through a sieve and season with salt and white pepper to taste.
While the soup is cooking, prepare the vanilla oil. Cut the vanilla bean lenghthwise and scrape out the seeds with your knife. Place the seeds into 50 ml of olive oil. Heat the vanilla-oil mixture to 45°C and put aside.
Rinse the scallop meat under running water and dry it with a paper towel. Brush the scallops with olive oil and sear them on both sides in a hot cast iron pan (1 minute per side). Season with salt and pepper to taste.