Place the 2 Quart Saucepan over medium heat and add the hoisin sauce, sesame oil, 2 table spoons soy sauce, rice vinegar, agave syrup, veggie broth, garlic, ginger and cornstarch. Bring to a simmer until the mixture thickens (about 3 minutes). Remove it from the heat and set aside.
Heat the remaining 2 tablespoons sesame oil and 2 tablespoons soy sauce in the 12" Large Skillet over medium to high heat. Add the seitan and fry until lightly browned. Add the scallions, bell pepper, asparagus, shiitakes and broccoli and stir-fry another 2–3 minutes, until the veggies are crips-tender.
Add the sauce to the pan and stir well. Cook for another 2-3 minutes, until the broccoli has softened.