Creating Slow Cooker Mongolian Chicken is simple when you follow these steps:

1. Prepare Chicken: Cut the chicken into bite-sized pieces and place them in the slow cooker.
2. Mix Sauce: In a bowl, combine soy sauce, brown sugar, vegetable oil, minced garlic, minced ginger, and red pepper flakes (if using).
3. Combine: Pour the sauce mixture over the chicken in the slow cooker, ensuring all pieces are coated well.
4. Cook: Cover the slow cooker and set it to cook on low for 4-6 hours or on high for 2-3 hours.
5. Thicken Sauce (optional): About 30 minutes before serving, mix cornstarch with water to create a slurry. Stir this into the slow cooker to thicken the sauce.
6. Check for Doneness: Ensure the chicken is fully cooked and tender. It should easily shred with a fork.
7. Garnish: Just before serving, sprinkle sliced green onions on top for added flavor and color.
8. Serve: Enjoy your Slow Cooker Mongolian Chicken over rice or noodles for a complete meal.

These straightforward steps will guide you in creating this incredible dish effortlessly.