Combine water and porcini in med. bowl. Let stand until porcini
soften,
about 40 mins. Drain; reserve soaking liquid. Chop porcini coarsely.
Heat oil in heavy lg. skillet over med-high heat. Add fresh mushrooms
and garlic and saute until brown, about 6 mins. Add porcini and
saute
until fragrant, about 4 mins. Add butter and thyme; stir 1 min.
Add
broth and 1.1/4 cups reserved mushroom soaking liquid.
Boil until sauce thickens slightly, about 5 mins. Mix in 4 tbsp
cheese.
(Can be prepared 1 hour ahead). Let stand at room temp.
Cook pasta in lg. pot of boiling salted water until just tender
but still
firm to bite. Bring sauce to simmer over med-high heat.
Drain
pasta. Add
to sauce; toss. Season with salt and pepper. Transfer pasta to
bowl. Top
with 4 tbsp cheese.
From Sue Woodward
Source: Bon Appetit, 9/95