Boil water and add the chicken of the wood powder. Reduce heat and cook for 2 minutes while stirring to obtain a paste. Cool down in the fridge.
Using a mixer, blend the egg yolks, mustard, vinaigre, salt and garlic. Gradually add the olive oil and end with the mushrooms powder paste.
Keep 1 week in the fridge.
Can be used as a fondue sauce for meat.