
Combine water and dried porcini mushrooms in a small bowl; let stand 30 Minutes to hydrate. Drain porcini through a sieve over a small bowl, squeezing to extract liquid. Reserve 1 1/2 cups liquid. Rinse porcini and drain. Chop coarsely and set aside.
Heat oil in a large saute pan over medium-high heat. Add onion and saute 5 Minutes. Add garlic; saute 30 seconds more. Add shiitake and cremini mushrooms and salt. Saute 5 Minutes or until mushrooms begin to brown and release moisture. Stir in porcini, wine and soy sauce. Cook about 5 Minutes or until the liquid is almost evaporated, stirring frequently. Add reserved porcini soaking liquid; bring to a simmer. Cook until liquid is reduced to 3/4 cup, about 10 Minutes. Remove from heat. Season with pepper.
Scald milk in a small saucepan. In a large saucepan, melt butter over medium heat. Add flour, stirring constantly with a whisk, and cook 1 minute until bubbly. Gradually add milk, stirring constantly. Bring to a simmer. Cook over low heat for about 8 Minutes or until the sauce thickens, stirring frequently. Remove from heat and add salt, pepper and nutmeg.
Preheat oven to 350 degrees. Lightly grease the bottom of a 9x13 baking dish. Spread 1 cup cream sauce in the dish. Arrange 3 lasagna noodles on top; spread 1 cup cream sauce on top of noodles. Top with 1 cup mushroom sauce. Sprinkle 1/4 cup parmesan cheese. Repeat layer three times. (4 layers in total) Cover with foil. Place dish on a baking sheet. Bake for 30 Minutes. Uncover lasagna and bake 15 Minutes more or until cheese melts.
