1.Cover each chicken breast with plastic wrap and lightly flatten with a rolling pin. Season well with freshly ground pepper.
2.Melt butter in a large frying pan on medium. Cook chicken breasts for 3 minutes each side, until golden and almost cooked through. Remove to a platter and keep warm.
3.Reduce heat to low and add onion. Cook for 5 minutes, stirring, until soft. Increase heat to medium and add wine. Simmer for 1 minute.
4.Stir in cream. Cook for another 3 minutes, until reduced slightly. Add basil and season.
5.Return chicken to pan for 1 minute, until heated through.
6.Serve with potatoes and zucchini.