Cut the Rooster potatoes into quarters and place them in a pot of water. Bring to a boil and cook until tender. Drain and leave to dry.
Cut the mushrooms into halves or quarters if they are big. Slice the pepper into strips and cut the pak choi into bite-sized pieces. Grate the ginger and finely slice the spring onions, coriander, and chilli pepper.
In a small bowl, combine the soy sauce, peanut butter, ginger, curry paste, lime juice, and honey. Add 2 tbsp of olive oil (or sesame oil) and whisk to create a smooth consistency. Season with salt and pepper.
Heat olive oil in a wok over medium heat. and add the pepper and pak choi. Fry for 5 minutes before adding the mushrooms, spring onions, and chilli pepper. Sauté until the vegetables are starting to brown. Add in the potatoes and the sauce. Bring to a simmer and add the soybean sprouts. Remove from the heat and season with salt and pepper.