Preheat your oven to 400°F if baking the meatballs, or prepare a non-stick skillet for pan-searing.
In a bowl, combine the lean ground beef, egg white, finely minced garlic, chopped fresh basil, salt, and pepper. Mix gently until just combined to avoid tough meatballs.
Form the mixture into small meatballs, approximately 1 to 1.5 inches in diameter.
Choose to either bake the meatballs on a parchment-lined baking sheet for 15-18 minutes or pan-sear them in a lightly heated non-stick skillet until browned on all sides and cooked through.
While the meatballs are cooking, prepare the fresh tomato sauce. Coarsely chop the two medium tomatoes and quarter the red onion. In a small saucepan, warm the olive oil over medium heat, then add the red onion and garlic (if additional garlic is desired) and sauté until softened.
Add the chopped tomatoes and a pinch of salt and pepper to the pan. Simmer for about 5-7 minutes until the tomatoes break down into a chunky sauce.
Meanwhile, cook the whole grain spaghetti according to package instructions if not already prepared, ensuring it reaches an al dente texture.
Assemble the dish by placing the cooked spaghetti on a plate, topping it with the fresh tomato sauce, and then arranging the lean beef meatballs on top.
Garnish with extra fresh basil if desired and serve warm.