For the aïoli (garlic mayonnaise), all the ingredients must be at the same temperature. Peel and press the garlic. Beat the egg and mustard in a tall mixing bowl with a chopping stick. Beat in approx. 1/8 l oil, first drop by drop, then in a thin stream. Stir in garlic and soured milk. Season the aïoli with salt and pepper, chill
Clean and possibly wash mushrooms. Heat 1-2 tablespoons of oil in a large pan. Fry the mushrooms in it for 8-10 minutes in portions, turning them frequently.
Wash the thyme and, except for something to garnish, pluck it. Add to the mushrooms and fry briefly. Season mushroom pan with salt and pepper and arrange. Garnish with the rest of the thyme. Serve with aïoli