Preheat the oven to 375 degrees F.

In a large cast iron enamelled pot (I use a 5 quart pot), heat the olive oil over a medium heat.

Generously season the chicken thighs with salt and pepper on both sides.

Brown the chicken thighs in the pot in batches. 12 chicken thighs will likely be 3 batches. Place the brown chicken thighs on a plate while you cook the other chicken thighs.

Cut the green end off the leak and the root tip. Slice the leek lengthwise and wash any sand out from in between the layers. Slice the leek into thin half moons.

When the chicken thighs are browned, turn down the heat and add the leeks, minced garlic and mushrooms. Cook until the leek has softened and the mushrooms have started to cook down a little, about 5 minutes.

Add a big pinch of salt and pepper and the dried herbs.

Add the white wine and scrape up any brown bits from the bottom of the pot.

Add in the chicken broth and return the chicken thighs to the pot.

Put the pot in the preheated oven with the lid on and cook for 45 minutes to an hour. You can cook it entirely on the stovetop, whatever is your preference.

After it has been cooking in the oven for 45 minutes, put the pot back on the stovetop and remove the lid. Add the cream and cook over a medium heat for 20 minutes to a half hour with the lid off. You are looking for the sauce to be the consistency of a thick gravy or a rich cream of mushroom soup.

Serve over a mix of mashed regular potatoes and sweet potatoes.