Linguini With Mushrooms

I borrowed a book from my neighbor called The New Pasta Cookbook and I'm putting the recipes I want to try on here. The picture looks awesome!

• Ready In: 2 hrs
• Serves: 4
• Yields: 4 plates

Ingredients

• 1⁄2 ounce dried porcini mushrooms
• 2  tablespoons butter
• 1  small onion, finely chopped
• 1  lb  very large button mushroom, sliced
• 1  tablespoon  chopped fresh sage (Don't substitute dried)
• 1  tablespoon  finely chopped fresh parsley
•  salt and fresh black pepper, to taste
• 1  lb linguine (fresh) or 3⁄4 lb  dried linguine
• 1⁄3 cup  freshly grated parmesan cheese

Directions

1. Soak porcini mushrooms in 3/4 cup warm water for 45 to 60 minutes.
2. Drain off liquid and filter it through muslin or a paper coffee filter to remove grit. Finely slice the rehydrated mushrooms.
3. Melt half the butter in a frying pan and gently saute onion until soft and golden.
4. Add porcini and filtered mushroom liquid and cook until liquid has evaporated. Add remaining butter, button mushrooms and herbs. Season well and gently simmer, covered, for 15 to 20 minutes.
5. Meanwhile, cook pasta in boiling salted water until al dente; drain and toss with the sauce and parmesan.