Start by slicing boneless, skinless chicken breast or thighs into thin strips. In a bowl, combine the chicken with soy sauce and cornstarch, ensuring all pieces are well-coated. Let the mixture marinate for about 10 minutes at room temperature.

While the chicken marinates, heat 2 tablespoons of vegetable oil in a large skillet or wok over medium-high heat. Wait for the oil to shimmer, indicating it's hot enough for cooking.

Add the marinated chicken to the hot oil, spreading it out in a single layer. Stir-fry the chicken for 5 to 7 minutes until it’s golden brown and fully cooked through.

Once the chicken is cooked, push it to one side of the pan, and add 2 minced garlic cloves to the other side. Stir the garlic for about 1-2 minutes, or until it becomes fragrant.

Introduce shredded cabbage, carrots, and sliced mushrooms to the skillet. Stir-fry these vegetables for 2 to 3 minutes until they are tender yet still crisp.

Pour hoisin sauce over the chicken and vegetable mixture, stirring thoroughly to coat all the ingredients. Cook for an additional 1-2 minutes.

In a separate pan, warm your moo shu pancakes or flour tortillas for about 30 seconds on each side over medium heat until pliable.

Spoon a generous portion of the chicken and vegetable filling onto each pancake. Fold in the sides and roll it up tightly.

Place the assembled wraps on a serving platter and sprinkle with optional garnishes if desired.