Soak the dried mushrooms in the boiling water, covered, for 30 minutes.
In a saucepan, sautè the chopped fresh mushrooms, onion and garlic in the butter for 5 minutes. Cover, turn flame to very low, and sweat the mushrooms for about 20 minutes, stirring occasionally.
Strain the liquid off the dried mushrooms, reserving the stock for the soup.
Set aside a few mushrooms to use as garnish, and slice them.
In a food processor, place the rest of the strained dried mushrooms and all the sauteed mushrooms. Add the cream and puree until smooth. Set aside.
In a saucepan melt 1 Tbl. butter. Whisk in 1 Tbl. flour. Gradually whisk in the mushroom soaking liquid. Simmer over very low heat. Add the pureed mushrooms, cream and the lemon juice. Mix well and add a little water as needed to the right thickness, not too thick but coats the back of a spoon.
Taste for salt and pepper.
Serve garnished with the mushroom slices.
Recipe By Jane O'Riordan