1. Heat a large frying pan and add the olive oil, fry the chicken for 5 minutes on each side, or until cooked through.
2. Add the lemon juice and salt and pepper. Add the white wine and reduce for 30 seconds. Coat the knob of butter in flour, and drop in the mixture to thicken.
3. Bring a pan of water to the boil and cook the green beans for 3-4 minutes, drain.
4. Put the beans on a plate, top with the chicken, drizzle over the sauce and serve.