Cut mushrooms into quarters. Dice chicken breast, zucchini, onion, and red bell pepper into bite-sized pieces. Trim enoki mushrooms and cut in half.

Mix 1 tbsp of cornstarch with a small amount of water to create a slurry, then add more water and mix well.

Slice garlic thinly and sauté in a heated pan with oil until translucent. Add onion and sauté until transparent, then add zucchini and mushrooms.

Add red bell pepper and chicken breast to the pan. Stir-fry and season with 1 tbsp oyster sauce. Adjust seasoning to taste.

Pour the cornstarch slurry into the pan and stir until the sauce thickens. Turn off the heat and mix in enoki mushrooms and parsley.