Melt 1 tbsp of the butter with the oil in a saucepan and fry the garlic, leeks and spring onions until softened. Stir in the mushrooms and fry for a further 2 minutes. Remove the vegetables from the pan with a slotted spoon.
Add the chicken pieces to the pan and brown on all sides. Return the vegetables to the pan and add the wine, stock, tomatoes, bay leaf and seasoning to taste. Bring to a boil, then cover and simmer for 40 minutes or until the chicken is cooked.
Lift out the chicken pieces and keep them hot on a serving plate. Boil the sauce to reduce it slightly.
Mix the remaining butter with the flour and add to the sauce in small pieces. Stir until thickened. Discard the bay leaf, and taste and adjust the seasoning. Throw in a dash of Tabasco for heat.
Serve over cooked linguini, place chicken over linquini then pour the sauce over the chicken and sprinkle with chopped parsley.