Slow Cooker Beef and Broccoli

Name: Slow Cooker Beef and Broccoli
Prep time: 15 min
Cook time: 4 h 30 min
Total time: 4 h 45 min
Yield: 6
Ingredients: Ingredients; Sauce (Homemade Option); 1/2 cup low-sodium soy sauce; 1/3 cup beef broth; 1/4 cup oyster sauce; 2 tablespoons brown sugar; 2 tablespoons cornstarch; 2 tablespoons rice vinegar; 1 tablespoon sesame oil; 1/2 teaspoon red pepper flakes (optional); 1/4 teaspoon black pepper; 2 lbs beef chuck roast or flank steak, cut into thin strips (about 1/4-inch thick); 4 cups fresh broccoli florets; 1 medium onion, sliced; 3 cloves garlic, minced; 1 tablespoon fresh ginger, grated; 2 tablespoons vegetable oil; 1 tablespoon sesame seeds (optional, for garnish); 3 green onions, sliced (for garnish); Cooked white or brown rice for serving; Store-Bought Alternative; 1 bottle (12-14 oz) teriyaki sauce or beef and broccoli stir-fry sauce; 2 tablespoons cornstarch mixed with 2 tablespoons water (for thickening if needed)