Preheat oven to 375 degrees.
In a large skillet over medium heat, add 1-tablespoon olive oil and the smoked sausage. Add 4 cups of the smoked tomato marinara sauce and 2 tablespoons of tomato paste. Mix together and let cook 5 minutes to combine.
In a medium bowl combine the ricotta, egg, salt, pepper, and nutmeg.
Spread ½ cup of the tomato sauce evenly on the bottom of a 9x13 baking dish. Layer with 3 lasagna noodles. Spread 1/3 of the ricotta mixture over the noodles. Add 1/3 of the mozzarella, ¼ cup Parmesan cheese, and 1 cup of the smoked tomato sauce.
Repeat with noodles, ricotta mix, cheeses, and sauce 2 more times. Cover with 3 noodles. Sprinkle with remaining mozzarella and sauce. Cover with foil.
Bake lasagna, covered with foil, for 40 minutes. Uncover and bake about 15 more minutes, until heated through and liquid is bubbly. Let stand for about 10 minutes before serving.