In a large pot of boiling water, cook the pasta according to package directions. Drain and set aside.
In a large skillet over medium-high heat, brown ground beef until no longer pink.
Drain fat as needed, then add garlic and cook until fragrant, about 1 minute.
Add soy sauce, beef broth, brown sugar, hoisin sauce, ginger, red pepper flake, and black pepper. Stir to combine.
Dissolve cornstarch in 2 tablespoons cold water and add to ground beef. Stir and bring to a gentle boil. Once sauce has thickened, add noodles and stir to combine.
Let noodles sit in sauce 2-3 minutes to absorb some flavor. Top with green onions and serve. Enjoy!
