Boil lasagna noodles until al dente; drain and set aside.
Sauté onion and garlic in olive oil until fragrant.
Brown ground beef, drain excess fat.
Add crushed tomatoes, tomato paste, and seasonings; simmer 15-20 minutes.
Mix ricotta, egg, and parsley in a bowl.
Layer in baking dish: sauce, noodles, ricotta mixture, mozzarella, Parmesan, meat sauce. Repeat 3 times.
Cover with foil and bake at 375°F for 25 minutes.
Remove foil and bake 25-30 more minutes until golden and bubbly.
Rest 10-15 minutes before slicing and serving.