In a mixing bowl, combine the ground beef, Italian-seasoned bread crumbs, sea salt, black pepper, and egg until just combined; do not overmix.
Portion the mixture and shape into 12 evenly sized meatballs.
Place the all-purpose flour in a shallow bowl and lightly dredge each meatball, shaking off excess flour.
Heat 3 tablespoons olive oil in a large skillet or Dutch oven over medium heat.
Add the meatballs and brown on all sides, about 6 minutes total; they should be browned but not fully cooked. Remove and set aside.
If desired, wipe out excess grease from the skillet, then add the pasta sauce and bring it to a gentle simmer.
Gently nestle the browned meatballs into the simmering sauce, cover, and cook for about 20 minutes or until meatballs are cooked through.
Meanwhile, bring a 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.
