Heat the oil and butter in a heavy based frying pan over a medium-high heat. Sauté the chicken breasts for 2-3 minutes on each side or until golden brown. Transfer to a plate.

In the same pan use the remaining butter mixture to gently fry the onion and garlic over a medium heat until really soft, about 10 minutes. Add the wine and simmer for a few minutes. Then add the stock, bring to the boil and simmer for a minute before whisking in the cream, 2 tbsp Organic Lemon Mustard and half of the fresh tarragon. Bring back to the boil and whisk thoroughly. Return the chicken breasts to the pan, cook for 7-10 minutes or until cooked through. Scatter over the remaining tarragon and season to taste.

Serve the chicken with the sauce and rice and steamed green beans. cook the rest.