Preheat oven to 350 degrees F.
Sauté chopped scallions and garlic in 2T of the olive oil, constantly stirring until the garlic is lightly golden, about 5 minutes.
Mix the sautéed scallions and garlic, plus the salt and half of the basil and oregano into the ricotta.
Sauté spinach and mushrooms in the remaining oil until the mushrooms are lightly browned but still plump, about 5 minutes. Drain off liquid.
Take two sheets of egg matzo, one at a time, and run briefly under cold water to lightly coat. Shake off excess. Place the two sheets side by side on the bottom of a 9" x 13" baking dish. If the matzo overlaps, break off the overlap and rearrange pieces as necessary to fill the layer.
Spread half of the ricotta mixture evenly in a layer over the pieces of matzo.
Arrange half the spinach and mushrooms evenly over the ricotta layer.
Spread a third of the tomato sauce over the spinach layer.
Sprinkle a cup of the shredded mozzarella evenly over the tomato sauce.
Sprinkle 1T of the parmesan evenly over the mozzarella.
Wet two more sheets of matzo as before, then lay on top of the cheese, breaking and rearranging as necessary to form a single layer, and repeat steps 6-10.
Wet two sheets of matzo as before and lay on top, breaking and rearranging as necessary to form a single layer.
Spread the remaining tomato sauce over the top, followed by the remaining mozzarella and then a layer of the remaining parmesan. Sprinkle the remaining basil and oregano on top. Optional: garnish in the center with a sprig of fresh Italian parsley, pressing the parsley gently into the cheese.
Bake uncovered on the middle rack of the oven until cheese browns, about 30-45 minutes. Bring immediately to the party, covered with foil, or save for the next day and reheat at 350° for 20 minutes before bringing.