Place the sliced leeks in a roasting tin, drizzle olive oil over them and season with salt and pepper. Sprinkle the garlic, lemon zest and thyme over them.
Pour the chicken stock and cream into the tin and mix everything well.
Place the chicken thighs in the tin skin side up and roast for 35–40 minutes, until the chicken is cooked through and the sauce is bubbling and slightly thickened.
Finish with a squeeze of lemon juice and a sprinkle of fresh chopped parsley.
