Infuse the diced chilli in 100ml hot olive oil and set aside.
Pan-fry the chicken breasts in butter and olive oil until cooked through.
Sauté the chopped onions in butter until well coloured.
De-glaze the onion pan with red wine and balsamic vinegar.
Add 700ml chicken stock and reduce the liquid by half.
Sauté wiped and sliced mushrooms in a very hot pan with butter and oil.
Strain the reduced stock, add the sautéed mushrooms and chopped parsley.
Season the sauce and add a knob of butter if needed.
Mix olive oil into the mashed potato and place in the center of the plates.
Slice chicken diagonally, place on potatoes, and spoon sauce around.
Briefly cook sugar snap peas, drizzle with chilli oil, and serve alongside.