In a bowl, mix the mushroom stock with soy sauce, maple syrup, sriracha sauce and rice vinegar. Add chopped green chilies to the bowl too, if using.
In another small bowl, make a slurry by mixing cornstarch with ¼ cup water. Mix the cornstarch into the water until no lumps remain.
In a wok heat a tablespoon of sesame oil over high heat. Stir in the broken red chili peppers and the ginger garlic paste and saute for a minute until the ginger and garlic are very aromatic and don't smell raw. Keep stirring the ingredients in the wok so they don't burn.
Add all the vegetables to the wok: bell peppers, broccoli, purple cabbage, mushrooms and carrots. Continue to stir-fry over high heat for 2-3 minutes or until the veggies are beginning to get tender.
Stir in the prepared sauce and mix well. Bring the sauce to a boil, then add the cornstarch slurry to the wok and mix well.
When the sauce returns to a boil it will thicken up and become more translucent. At this time stir in the peanuts and check if you need more salt.
Stir in the scallions. Turn off heat and serve the kung pao vegetables hot or warm.