Sauté the onion and garlic. In a large pot, heat the olive oil over medium heat. Add the onion and cook, stirring frequently, until translucent, about 4-5 minutes. Add the garlic and cook for 30 seconds, stirring constantly.
Brown the meat. Add the ground beef to the pot and cook, stirring frequently, until browned, about 6-8 minutes.
Simmer the sauce. Add the crushed tomatoes, tomato paste, tomato sauce, broth, sugar, basil, 1 teaspoon oregano, 2 teaspoons kosher salt, and the black pepper. Stir well, then bring to a simmer. Cover and cook over medium-low heat for 2 hours, stirring occasionally.
Cook The Noodles + Make the Ricotta Filling
Prep. Preheat the oven to 375˚F. Get a 9x13 baking dish and set aside.
Cook the noodles. Bring a large pot of salted water to boil and cook the lasagna noodles according to the package instructions. Rinse the cooked noodles with cold water and set aside.
Make the ricotta filling. In a medium bowl, combine the ricotta, remaining 1/2 teaspoon salt, remaining 1/2 teaspoon oregano, and the egg. Stir well to combine.
Assemble the layers. Put your lasagna together in the following order:
Start layering the ingredients. Spoon about 1½ cups of the prepared sauce over the bottom of your baking dish. Top with 5 lasagna noodles, overlapping them a bit. Spread half the ricotta mixture over the noodles. Top with 1½ cups of mozzarella and ¼ cup of Parmesan.
Continue to layer. Spoon 1½ cups of sauce over the cheese. Top with 5 lasagna noodles, overlapping them a bit. Spread remaining ricotta mixture over the noodles. Top with 2 cups of mozzarella and ¼ cup Parmesan.
Finish the layers. Spoon about 1½ cups of sauce over the cheese. Top with remaining 5 noodles, overlapping them a bit. Spoon remaining sauce on top of the noodles (about 1½ cups). Top with remaining 1½ cups of mozzarella and remaining ¼ cup of Parmesan.
Cook the Lasagna
Bake. Spray a piece of tin foil with PAM or baking spray, then cover the lasagna (sprayed side down) and bake it covered for 25 minutes.
Remove the cover and continue to bake. Remove the foil and bake the lasagna for 25 minutes more or until the lasagna is bubbly and the cheese has melted.
Rest and serve. Let the baked lasagna rest for 15 minutes before serving.