Heat the olive oil in a small Dutch oven over medium heat. Add the onions and mushrooms, then cook for 3-4 minutes.
Add the ground beef, bell pepper, and chopped garlic, then season with sea salt and freshly cracked pepper; cook for 4-5 minutes, making sure to crumble the ground beef as it cooks.
Drain any excess grease from the Dutch oven, then add the marinara sauce and stir.
Simmer the sauce for 1-2 hours to allow flavors time to combine.
Cook the elbow macaroni in a large pot of salted water according to the package instructions, and drain completely.
Combine the macaroni with the sauce, add the fresh basil, and mix.
Simmer for 15 minutes to allow the sauce to soak into the noodles.
Top with Asiago cheese if desired and serve. Enjoy.