Ground Beef Lo Mein

Name: Ground Beef Lo Mein
Ingredients: 6 ounces spaghetti; 1 pound lean ground beef; 3 tablespoons hoisin sauce; 2 tablespoons reduced-sodium soy sauce; 2 tablespoons oyster sauce; 2 tablespoons water; 1 tablespoon dry sherry; 2 teaspoons sesame oil; 2 teaspoons cornstarch; 1 teaspoon brown sugar; 1 tablespoon olive oil; 1 red bell pepper, cored and sliced vertically; 1 sweet onion, peeled and sliced vertically; 1 cup snow peas; 1 stalk celery, sliced; 2 teaspoons minced fresh ginger root; 1 teaspoon minced garlic; 1 pinch red pepper flakes; 1 tablespoon thinly sliced green onion