In a mixing bowl combine the ground beef, Italian seasoned bread crumbs, sea salt, black pepper, and egg until just mixed; avoid overworking.
Portion the mixture into 12 equal pieces and shape each into a meatball without packing tightly.
Spread the all-purpose flour on a plate and lightly dredge each meatball, shaking off excess flour.
Heat 3 tablespoons olive oil in a large skillet or Dutch oven over medium heat until shimmering.
Add the meatballs and brown on all sides, about 6 minutes total; they should be browned but not cooked through. Transfer to a plate and set aside.
Wipe out excess grease from the skillet if desired, then add the pasta sauce and bring to a simmer over medium-low heat.
Gently nestle the browned meatballs into the simmering sauce, cover, and simmer for about 20 minutes or until meatballs are cooked through.
Meanwhile, bring a large pot of salted water to a boil and cook the spaghetti according to package directions until al dente; drain.
Serve the meatballs and sauce over the hot spaghetti and sprinkle with grated Parmesan cheese.