Cut the chicken into strips. Set aside. Slice the mushrooms and set aside separately. Finely slice the red bell pepper and set aside separately. Grate the garlic and the ginger, add to the bowl with the pepper strips.
Heat 1 tablespoon of the oil in a large skillet or non-stick pan. Fry the chicken strips in two batches until golden on all sides, this will take about 2-3 minutes per batch. Remove from the pan.
Heat the second tablespoon oil and fry the mushrooms for about 2 minutes, stirring often. Add the red peppers, grated ginger, garlic, cayenne pepper and cook for another 3-4 minutes, stirring often, until the mushrooms are golden and the peppers softer.
In the meantime, whisk together the coconut milk and the peanut butter in a bowl until smooth. Add to the pan together with the chicken, a little salt and pepper. Reduce the heat and simmer for about 5 minutes or until the vegetables are soft and the chicken cooked through.
The sauce should have thickened slightly. If too thick, you can thin it slightly with regular milk. Adjust the taste with lime juice, salt and pepper.
While the sauce cooks, heat a large pan over medium heat. Roast the peanuts, shaking the pan often until fragrant and golden. Transfer to a plate and let cool.
Sprinkle the peanut butter chicken with peanuts and parsley and serve immediately with rice and some lime wedges on the side.