In a medium bowl, toss the Original Pieces in the baking powder making sure each piece is evenly coated. Preheat a large skillet or wok over medium heat with 2 tbsp of cooking oil. Add the coated Original Pieces to the skillet in one even layer and sear for 5 to 6 minutes on each side, or until golden brown. Remove to a clean plate and reserve.
Meanwhile, prepare your sauce. In a small bowl, whisk together the water or vegetable stock, soy sauce, hoisin sauce, rice vinegar, sugar and cornstarch until completely smooth and set aside.
Place the skillet or wok over high heat with 1 tbsp cooking oil. When hot, add scallions (reserving some of the greens for garnish) and red and green bell peppers. Stir fry for 3 to 4 minutes until just softened and beginning to brown at the edges. Add the garlic, ginger and Sichuan peppercorns and stir fry until fragrant—1 to 2 minutes more.
Carefully pour in your reserved sauce, chiles, stir-fried Original Pieces and stir. When the mixture is bubbling, turn heat to low and simmer for 3 to 4 minutes more or until the sauce is thick and glossy. Drizzle in sesame oil and add peanuts, reserving a few for garnish. Stir and remove from heat.
To serve, spoon over freshly steamed white rice and garnish with the reserved peanuts, sesame seeds and scallions.
If you don’t have access to Sichuan peppercorns (a staple spice of the Sichuan cuisine, famous for its “tingling” effect), substitute with the same amount of ground black or white pepper.