Season chicken with salt and pepper and coat with flour.
Fry chicken in oil and half the butter for 2 minutes per side until golden.
Fry bacon and mushrooms in remaining butter, then caramelise with shallots and sugar.
Deglaze pan with wine and add to chicken with stock, tomato purée, and tarragon.
Simmer for 30-40 minutes until chicken is cooked through and sauce reduces.
Boil potatoes in salted water for 12-15 minutes until tender.
Drain potatoes and steam dry over heat for one minute.
Mash potatoes with butter and milk until smooth.
Add tomatoes and parsley to chicken and simmer for 2 minutes.
Serve chicken with sauce and a portion of mash.