Place a large pot of water on to boil and add the potatoes, leave to cook for 20 minutes
Heat a splash of oil in a frying pan and fry the leeks until softened, season if needed
Once cooked remove from pan, add another splash and fry the chicken until browned and cooked through, around 8 mins each side
When the chicken is cooked add the creme fraiche, cider and horseradish mustard, leek and a splash of water. Stir to combine and cook for 3 mins. Spoon sauce over chicken, cover pan and set aside.
Heat oil in another frying pan and add the mustard seeds, cook for 30 seconds, then add the green beans and some salt and pepper. Stir fry for a few minutes then add a splash of water, reduce heat and cover pan to steam
Drain your potatoes, mash with a little butter and/or milk if you like, season if needed
Remove your chicken from pan and slice. Serve chicken on a bed of mash, a side of beans and cover in creamy sauce
Enjoy