In a skillet, put spoonfuls of oil, a tablespoon of lemon juice and mushrooms and cook over medium heat.
Add 150 ml of water and cook for 5 minutes.
Transfer the contents to the mixer bowl and make puree.
Place the puree in a saucepan and add the cooking cream. Bring to the boil, remove from the fire and put the egg yolk. Mix until combined and let rest.