Preheat your dutch oven over medium heat for 3 minutes. Add the ground beef, breaking it up into small pieces with a wooden spoon. Season with a teaspoon of kosher salt and cook until no pink remains, stirring occasionally.

Once the meat is browned, drain the fat completely and set the beef aside. Add 1 teaspoon of olive oil to the pan. When shimmering, add the diced onions and bell pepper. Cook until they begin to soften, then push them aside. Add the remaining oil to the pot, followed by the garlic. Cook for 2 minutes, then stir in the ground beef.

Stir in the tomato paste, coating the garlic, and let it deepen in color and become fragrant. Move the paste and garlic aside and toast the fennel seeds, stirring constantly for a minute or two.

Pour in the crushed tomatoes, tomato sauce, water, and balsamic vinegar. Stir everything together, then mix in all the dry seasonings. Taste the sauce and adjust with brown sugar if needed to balance the flavor. Add more salt if necessary, then drop in the parmesan rind. Cover and reduce the heat to medium-low.

After an hour, give the sauce a stir and taste again, adjusting the seasoning if needed. Continue cooking for 2 more hours, allowing the sauce to reduce and thicken to your liking. Once thickened, remove the parmesan rind and stir in the minced basil. Simmer for an additional 15 minutes.

For a richer flavor, you can continue simmering the sauce on medium-low for 2-4 hours, on low for 6-18 hours, or in a 250°F oven for 8 hours.