Cut the chicken breasts in half, butterflied to make four thinner chicken breast pieces.
Mix together the flour, salt and pepper then coat the chicken pieces in it.
Add the butter and olive oil to a large skillet on medium high heat and cook the chicken in it 4-5 minutes on each side until golden brown.
Remove the chicken from the pan, add in the mushrooms and cook for 3-4 minutes until browned.
Add the chicken back in, pour in the chicken stock and wine and let simmer for 10 minutes before serving.