Add oil to a large skillet set over medium-high heat. Add garlic and ginger to the pan. Cook for 30-60 seconds, just until fragrant. Stir in the asparagus, pepper, and mushrooms. Cook for 3-4 minutes, until the veggies are slightly tender but still bright in color. Remove veggies to a plate and set aside.

While the veggies cook, whisk together the chicken broth, soy sauce, hoisin sauce, brown sugar, and sesame oil in a small bowl or liquid measuring cup.

In a separate small bowl, combine the cornstarch with 2 tablespoons cold water and whisk until fully dissolved.

After removing the veggies, keep the skillet over medium-high heat. Add another teaspoon of oil if the skillet is dry. Add the chicken and cook for 2-3 minutes on each side, just until browned on the outside, but not quite fully cooked through.

Pour the soy sauce mixture on top of the chicken. Bring liquid to a simmer, then stir in the cornstarch mixture. Continue to cook, stirring frequently, until the sauce thickens, about 1 minute. Return veggies to the pan and toss to coat.

Garnish as desired and serve right away.