Bring a large pot of salted water to a boil and cook the whole wheat spaghetti according to package directions until al dente.
While the pasta cooks, finely dice the yellow onion, carrot, and celery, and mince the garlic clove.
Heat the extra virgin olive oil in a large skillet over medium-high heat.
Add the ground beef to the skillet, breaking it up with a wooden spoon, and cook until browned and no longer pink.
Stir in the diced onion, carrot, and celery, sautéing for 5-7 minutes until the vegetables are softened and fragrant.
Add the minced garlic, sea salt, black pepper, and dried oregano, cooking for an additional 1 minute.
Pour in the tomato puree and stir to combine, then reduce the heat to low and let the sauce simmer for 10 minutes to allow flavors to meld.
Drain the spaghetti and add it directly to the skillet with the beef sauce, tossing well to coat the noodles.
Serve the pasta in a shallow bowl and top with a fresh dusting of parmesan cheese.