HEAT oven to 350°F.
MIX eggs, ricotta, spinach and 1/2 cup grated cheese until blended.
SPREAD 1 cup of the spaghetti sauce onto bottom of 13x9-inch baking dish; cover with layers of 1/3 of the noodles and half each of the ricotta mixture and sausage. Top with layers of 1/2 cup mozzarella and 1-1/2 cups of the remaining spaghetti sauce. Repeat all layers. Top with remaining noodles, sauce and mozzarella. Sprinkle with parsley; cover.
BAKE 1 hour 10 min. or until heated through, uncovering and topping with remaining grated cheese after 1 hour. Let stand 10 min. before cutting to serve.