Portobello and Summer Squash Lasagna

olive oil, divided

zucchini, sliced lengthwise very thin (about 1/8″), or summer squash

portobello mushroom caps, “gills” scraped out and sliced into 1/4″ pieces

ricotta cheese

eggs, lightly beaten

yellow onion, diced

minced garlic

marinara sauce

about 12 no-boil lasagna noodles

grated Mozzarella cheese + 3 oz Parmesan cheese

sea salt, divided

pepper