Preheat the oven to 350°F (175°C). Spray a 9x13-inch baking dish with nonstick spray and set aside.
Cook the lasagna noodles according to package directions, drain, and set aside.
In a large skillet over medium heat, cook the ground beef and Italian sausage until no longer pink. Drain any excess fat.
Add Stone House Seasoning, dried basil, dried oregano, pasta sauce, and tomato paste to the cooked meat. Simmer, stirring occasionally, until the sauce thickens, about 5–10 minutes.
In a large bowl, lightly beat the egg. Add softened cream cheese, Greek yogurt, 2 cups of the shredded mozzarella, 1/4 cup of the shredded Parmesan, and chopped parsley if using. Stir until smooth and well combined.
Spoon 1 cup of the meat sauce into the prepared baking dish and spread into an even layer.
Arrange a layer of lasagna noodles over the sauce, spread one-third of the cheese mixture over the noodles, then top with 1 cup of meat sauce. Repeat this noodle, cheese, and sauce layering two more times.
Top with a final layer of lasagna noodles and spread the remaining meat sauce over them. Cover the dish loosely with aluminum foil.
Bake covered for 40 minutes.
Remove the foil and sprinkle the remaining 2 cups mozzarella and 1/4 cup Parmesan over the lasagna. Bake uncovered until the cheese is melted and lightly browned, about 15 minutes.
Allow the lasagna to rest for 10 minutes before slicing and serving.