Rinse dried mushrooms under cold running water in a small strainer until they are free of all dirt and grit.
Combine dried mushrooms and Madeira in a small bowl, cover, and let stand for 1 hour, stirring occasionally.
Wipe fresh mushrooms with a damp paper towel.
Cutoff stems and save for another use.
Slice mushroom caps in half.
Melt half of the butter in a large skillet and add the halved fresh mushrooms.
Cook, stirring, over high heat for 5 minutes.
Lift the dried mushrooms carefully from the bowl with a slotted spoon.
Coarsely chop the dried mushrooms and add them, the remaining butter, shallots, garlic and parsley to the skillet and cook over low heat for another 10 minutes, stirring occasionally.
Pour the Madeira carefully into the skillet, leaving any sediment behind.
Season to taste with salt and pepper, turn out into a heated vegetable dish, and sprinkle with fresh lemon juice.