Cook ravioli according to package directions; drain and set aside. Meanwhile, saute mushroom, spinach, salt and pepper in olive oil.
Preheat oven to 450°. Using four lightly greased 16-ounce ramekins or crocks, layer ravioli with spoonfuls of mushroom-spinach mixture and ricotta. Cover with pasta sauce and shredded mozzarella. Bake for 10 minutes or until cheese is fully melted. Serve with additional hot pasta sauce, if desired.