Prep the vegetables: Cut the red bell pepper into thin strips (half lengthwise).
Cook the peppers: Heat a non-stick pan over medium heat, add the pepper strips (no oil), and cook until slightly softened.
Add cabbage and carrots: Add the shredded cabbage and julienned carrots (or coleslaw mix) to the pan and fry until the carrots begin to soften.
Add sauces: Stir in the soy sauce, teriyaki, and mushroom sauce. Continue to stir for 1–2 minutes before removing from heat.
Cool the filling: Transfer the filling to a bowl and place it in the fridge to cool.
Prepare the oven and batter: Preheat the oven to 190ºC (370ºF) and mix the batter ingredients together.
Prepare for rolling: Set up a clean surface or cutting board and a wide deep vessel for dipping the rice papers. Use a rinsed pan for dipping. Also, line a baking sheet with parchment paper.
Soak rice papers: Dip each rice paper four times: first deep to get fully wet, turn it over and repeat.
Press out excess water: Place the rice paper on the surface and gently press out excess water.
Roll the spring rolls: Place another wet rice paper on top, then add 2 tbsp of filling along a straight line about 5 cm from the edge.
Roll the spring rolls: Fold the side closest to you over the filling and tuck it under like a burrito.
Fold in the edges: After rolling a bit, fold in the edges to avoid too much filling escaping, ensuring they stay tight.
Seal the rolls: Roll the paper tightly to the end and use a little water or batter to seal the roll shut.
Brush and bake: Brush each spring roll with the batter and bake them for 25 minutes, until golden and crispy.
Prepare the sauce: While the rolls bake, mix together the sweet and sour sauce ingredients.
Serve: Best served fresh but allow the rolls to cool slightly before serving.