Combine porcini with boiling water. Let stand 20 minutes. Drain through fine sieve, reserving liquid. Chop.
Heat oil in saucepan over medium heat. Add shallots. shiitakes, porcini and crushed red pepper. Cook over medium-low heat, stirring 5 minutes, until mushrooms release their juices. Add wine and cook about 5 minute, or until almost dry.
Add porcini liquid, tomatoes, thyme, salt and pepper. Cover; increase heat to a simmer. Reduce heat to low, and cook, partially covered for 15 minutes.
Puree 1 cup sauce and return to pot. Stir in lemon juice and parsley. Taste for salt. Serve over ravioli, saving leftover sauce for another use.
Top with Wild Mushroom Ragu. Garnish with sage.