Bring a large pot of salted water to a boil. Add 8 ounces of spaghetti and cook until al dente, about 8–10 minutes. Reserve 1/4 cup of pasta water, then drain.

In a large skillet, heat 1 tablespoon of neutral oil over medium-high heat. Add 1 pound of ground beef and cook until browned, about 5–7 minutes.

Reduce heat to medium, add 4 cloves of minced garlic and 1 tablespoon of grated ginger to the skillet. Sauté until fragrant.

Stir in 3 tablespoons of soy sauce, 1.5 tablespoons of chili oil, 1 tablespoon of brown sugar, and 1 tablespoon of rice vinegar. Simmer for 2–3 minutes.

Add drained spaghetti to the skillet and toss with the beef and sauce mixture. Gradually add reserved pasta water if needed.

Drizzle 1 teaspoon of sesame oil and toss in 2 chopped green onions and 1 teaspoon of sesame seeds. Mix until well combined.

Serve hot, optionally drizzled with extra chili oil.