Heat the olive oil in a large Dutch oven over medium heat. Add the ground beef and the onion. Cook, stirring often to crumble the beef for 4-5 minutes. Add the carrots, roasted bell pepper, garlic, dried basil, dried oregano, crushed red pepper flakes, sea salt and freshly cracked pepper, to taste. Add the beef stock, tomato paste, crushed tomatoes, chopped tomatoes, and tomato sauce to the beef mixture as well as the sugar. Stir until well combined. Cover with a lid and reduce heat then simmer for 3-4 hours. Before serving add the fresh basil and parsley then stir to combine.
After the sauce has simmered, preheat the oven 350 degrees.
Cook lasagna noodles per instructions then lay them out on top of some parchment paper.
Combine the ricotta, spinach, 1/2 cup of mozzarella, 2 tbsp of Parmesan, egg, nutmeg, basil, parsley, garlic, sea salt and freshly cracked pepper, to taste, together in a large bowl; mix until well combined. Spoon a thin layer of the ricotta mixture down the entire length of the lasagna noodle. Repeat with the remaining noodles. Starting from one end, roll up. Repeat.
Coat a baking dish with cooking spray then spoon a layer of the slow simmered meat sauce in the bottom of the baking dish. Place the lasagna rolls, seam side down, into the baking dish. Cover each roll with sauce then add the remaining cup of mozzarella cheese and 2 tbsp Parmesan cheese equally to the top of each roll.
Cover with tin foil, and cook for 15 minutes. Remove the tin foil and continue baking for 5-10 minutes or until the cheese is melted.