SOAK porcinis in 1 cup boiling water until soft, about 8 min.
COOK ravioli, following package directions, but without salt. Reserve 1/2 cup pasta water. Drain.
HEAT oil in a large non-stick frying pan over medium-high. Add creminis. Cook, stirring until golden, 5 to 6 min. Add garlic and cook, stirring, for 30 sec. Sprinkle with flour and stir for 1 min. Add soaked mushrooms along with liquid, and season with salt and pepper. Boil, then reduce heat to medium-low. Simmer until slightly thickened, 1 to 2 min.
STIR ravioli, parmesan and reserved pasta water into sauce until cheese has melted, about 1 min. Sprinkle with parsley and more parmesan.