Mix first 6 ingredients in a small bowl, divide mix in half.
Cook spaghetti according to package directions, drain, cover and set aside.
Add 1 tbsp. oil to large skillet, add QuickSteak Beef, sear on one side, when meat begins to break apart, pour ½ of prepared sauce mix over cooking steak.
Turn patties, stir-fry until no longer pink, remove from pan, set aside.
Add 1 tbsp. oil to same skillet, add water chestnuts, green onions and red peppers, stir-fry one minute.
Add spinach and remaining sauce mix, stir until spinach is wilted, return steak to pan, combine with spinach, add the cooked spaghetti, heat through and sprinkle with chili pepper.