Season both sides of the chicken with salt, then start by adding rapeseed oil, then your chicken into a cast iron/stainless steel pan skin-side down. Increase the heat to medium and leave to sear for 8 minutes.
Once the skin is crispy and removed from the pan easily, rotate the chicken legs so that the crispy side is facing upwards. Pop in the oven for 30 - 35 minutes, or until completely cooked.
After this time, carefully remove the pan from the oven and place on the hob. Set the crispy chicken legs aside and remove the excess chicken fat from the pan, until you have around 2 tbsp left.
Add the onion into the pan and season with salt and pepper. Cook over a low/medium heat for around 4 minutes, then add the garlic to fry for a couple of minutes.
Next, add the mustard and creme fraiche. Stir to combine and heat through before slowly pouring the chicken stock into the pan.
Add the spinach and corn flour slurry. Cook for 2 minutes before adding the chicken legs back into the pan (crispy side still facing up and partly submerged).
Cook for around 3 minutes over a low heat to bring the chicken legs back up to temperature, then top with some fresh parsley. Serve with a lemon wedge and a side of new potatoes/baby potatoes.