Preheat the oven to 350℉. Spray a 9x13-inch casserole dish with cooking spray. Set aside.
Bring a large pot of salted water to a boil.
Cook the lasagna noodles according to package instructions, drain and set aside.
Prepare the meat sauce while the noodles cook: Heat the olive oil in a skillet over medium/high heat.
When the oil becomes fragrant add the Italian sausage and onions. Cook for 5-6 minutes, until there is no pink left in the sausage.
Add the garlic and cook for an additional minute.
Add the marinara sauce and set aside.
Prepare the filling: Place the cottage cheese, Parmesan cheese, salt, pepper, and eggs in a medium bowl.
Mix well and set aside.
Assemble the lasagna: Spread 1 cup of the meat sauce on the bottom of the casserole dish, covering the bottom of the pan. Layer 4 noodles on top of the sauce. Spread half of the cottage cheese mixture on top of the noodles. Sprinkle ½ cup of the mozzarella cheese on top of the cottage cheese. Spread ¾ cup of the meat sauce on top of the mozzarella. Repeat the steps until you get to the top layer of noodles.
Spread the remaining sauce over the noodles and sprinkle the remaining 1 cup of mozzarella on top of the sauce.
Cover the casserole dish with tin foil and bake for 25 minutes.
Remove the tin foil and bake for an additional 10 minutes.
Allow the lasagna to rest for 10 minutes before serving.