Remove the bones from the chicken thighs, if you like. Season with salt and lay the thighs skin-side down into a cold pan.
Place over a medium heat and let them cook without moving until the skin is deeply golden and crisp, about 8-10 minutes.
Flip and cook through on the second side, then lift onto a board to rest.
Slice the leeks, saving some of the white top to julienne.
Add the sliced leeks to the same pan and let them soften in the rendered chicken fat.
Splash in the white vinegar and Dijon mustard and let it cook off.
Add the chicken stock and simmer until the leeks turn silky.
Stir in the crème fraîche and parmesan so the sauce becomes smooth and lightly creamy.
Fold in the white beans with the chilli flakes and let everything warm through.
Slice the chicken and settle it back into the pan, spooning the sauce over the top.
Mix the parsley, dill, julienned leek and lemon juice in a small bowl.
Spoon the herb salad over each plate just before serving. Serve with a lemon wedge.
