Soak the dried mushrooms in 150ml water for half an hour. Bring to the boil in a saucepan and reduce the liquid to 75 ml.
Prepare the fresh wild mushrooms by trimming them and rinsing under cold water if necessary.
Break the ends of the asparagus stems and peel. Slice the shallot and finely chop the garlic.
Sweat the shallots in the butter for 5 minutes until soft. Add the garlic and thyme and cook for a further minute. Add the wine to the pan and reduce to 25 ml. Add the mushroom stock and the dried mushrooms and reduce this to 50ml. Add the double cream and bring to the boil. Add salt and pepper to taste and a drizzle of truffle oil. Pour the sauce through a sieve to remove the mushrooms and shallots.
Saute the fresh mushrooms in a frying pan with olive oil until golden brown. Season with salt and pepper and then arrange on plates.
While cooking the mushrooms, cook the asparagus in salted boiling water for 3 minutes until tender. Drain, season with salt and pepper and place on top of the mushrooms.
Use a hand blender to make the sauce into a foam. Spoon over the asparagus and around the plate. Serve immediately.