Preheat the oven to 350°F (175°C) and lightly grease a 13x9-inch baking pan.
In a large bowl, combine the ricotta cheese, eggs, grated Parmesan, parsley, and 1 cup of the mozzarella; mix until smooth and uniform.
Spread 1½ cups of the spaghetti sauce evenly over the bottom of the prepared pan.
Place four lasagna noodles over the sauce (fit three lengthwise and a shorter broken piece across if needed).
Spread about one-third of the ricotta mixture over the noodles, then top with 1 cup of sauce.
Repeat the layers: noodles, one-third of the ricotta mixture, and 1 cup sauce. Finish with a final layer of noodles, the remaining sauce, and sprinkle the remaining 1 cup mozzarella evenly on top.
Cover the pan with aluminum foil and bake for 45 minutes.
Remove the foil and continue baking for 10 more minutes until the top is melted and bubbly.
Let the lasagna rest for 10 minutes before slicing and serving.