Steam spinach until tender; press out excess moisture and chop
coarsely. Chop mushrooms and onions and mince garlic over
medium-high heat until onions are tender; drain excess liquid and
cool. Mix ricotta cheese, 2/3 cup Parmesan, egg, salt, pepper, basil
and oregano in large bowl. Add cooled spinach and mushroom-onion
mixture and mix on low speed until just blended. Cook lasagna
according to package directions; rinse under cool water and drain
thoroughly.
Place four lasagna strips in bottom of lightly oiled 9x13" pan,
overlapping slightly. Top with 2 c of spinach filling.
Sprinkle with 1-1/2 c shredded cheese and 1/3 c Parmesan. Repeat
layering two more times and top with remaining four lasagna strips.
Spread 1 cup of marinara or tomato-cream sauce over top and cover
tightly with foil. Preheat oven to 350 and bake, covered, for 1
hour. Remove from oven and keep warm at least 30 minutes before
cutting. Top with extra Parmesan cheese. (Can be refrigerated a day
in advance of baking if desired.)
