Steak or Seitan and Pepper Stir Fry

I will try this recipe from The Adaptable Feast, but will most probably use chicken instead of steak and tofu instead of seitan.

This Chinese-inspired dish relies on an agreeably garlicky black bean sauce for an authentic-tasting stir-fry that comes together in minutes. If you don't eat red meat, use boneless, skinless chicken thighs cut into bite-size pieces instead of steak.

1-1/2 teaspoons cornstarch
2 tablespoons soy sauce
4 teaspoons Chinese rice wine or dry sherry
1 teaspoon chili oil
5 oz seitan, cut into thin strips
12 oz sirloin steak, frozen until semi-firm, cut into 1/4-inch-thick strips
2 heaping tablespoons black bean-garlic sauce (Lee Kum Kee in red label)
1 teaspoon sugar
3 tablespoons vegetable stock or water
1 tablespoon Chinese rice wine or dry sherry
2 tablespoons plus 1 teaspoon vegetable oil
1 tablespoon peeled, minced ginger
1 tablespoon finely chopped garlic
1 medium onion, halved and thinly sliced through root end
1 large green pepper, thinly sliced
2 green onions, chopped
5 cups steamed rice

1. Combine the cornstarch and soy sauce in a medium bowl. Stir in the rice wine and chili oil.
2. VEGETARIAN: Transfer 1 tablespoon of the rice wine mixture to a small bowl and toss with the seitan; set aside.
3. Toss the meat in the remaining rice wine mixture and set aside.
4. In a small bowl or measuring cup, combine the black bean garlic sauce, sugar, stock, and rice wine; stir until the sugar is dissolved.
5. VEGETARIAN: Heat 2 teaspoons of the oil in a small saute pan until hot. Add the seitan and saute until it is crisped around the edges, about 2 minutes. Remove the pan from the heat and set aside.
6. Heat 1 tablespoon of the oil in a wok over medium-high heat, add the ginger and garlic, and stir-fry until fragrant, about 10 seconds. Add the onion and peppers and stir-fry until they are just singed, about 1 minute. Add the black bean-garlic sauce and stir-fry for 1 minute.
7. VEGETARIAN: Transfer one quarter of the vegetables in black bean-garlic sauce to the saute pan containing the seitan and stir to combine. Keep warm over medium-high heat.
8. Transfer the remaining vegetables in black bean-garlic sauce to a serving bowl. Return the wok to medium-high heat. Heat the remaining 2 teaspoons of oil, add the meat, and stir-fry until it is just cooked through, about 2 minutes. Return the reserved vegetables in black bean-garlic sauce to the wok, toss with the meat, and cook until the sauce is bubbly, about 1 minute.
9. Sprinkle both stir-fries with the green onions and serve with steamed rice.