Toss the chicken substitute (seitan, tofu, tempeh) with the garlic powder, thyme, oregano, cornstarch, salt and ground black pepper. If using beans you can add them directly to the rice, no need for this step and the next.
In a pot large enough to hold the rice, heat 1 tbsp oil. Add the meat substitute in a single layer and brown on all sides. Remove to a plate.
To the same pot, add the remaining oil and heat. Add the onions and garlic along with a pinch of salt and ground black pepper and cook for five minutes over medium-low heat until translucent.
Add the wine, if using, and cook the onions further, stirring a couple of times, until the moisture has evaporated.
Add the tomato paste to the pot with the tamari or soy sauce and stir well to mix, then add the bell peppers along with the thyme, oregano, sage, paprika and bell peppers. Mix well.
Add the rice to the pot and stir-fry it for a couple of minutes. Add the capers and saffron and the vegetable stock, if using, or water. Bring everything to a boil over medium-high heat and stir occasionally to make sure nothing is sticking to the bottom. Add salt and pepper.
Continue to cook the rice until it appears to have absorbed most of the water. Now stir in the reserved "chicken" pieces, cover the pot with a tight lid, turn the heat down to the lowest setting, and cook 20 minutes, undisturbed.
Let the rice stand another 10 minutes after cooking, then serve. Add parsley or another herb garnish, if you wish, before serving.