*With a wet marinade like this, the chicken skin would never crisp up in the oven and I’m not really a fan of the soft fatty texture you get when the skin doesn’t crisp. Ideally there would be such a thing as bone-in skinless thighs since roasting with the bone adds some extra flavor to the meat, but alas, I haven’t found it. You could of course buy bone-in skin-on chicken thighs and remove the skin yourself but I’m kind of lazy so I just let the mustard make up for any lost flavor.
Leeks are really dirty vegetables so I find it easier to chop and then wash them to get out all the dirt. And don’t forget to rinse your cutting board too.
The mustard and lemon will both break down the proteins in the raw chicken a little bit while marinating and at some point it will start to affect the texture of the chicken. That point starts around 8-10 hours so don’t leave it longer than that.