Season the chicken on all sides with salt, place on paper towels, and set aside and let come to room temp for 20 minutes.

In an ovenproof pan, melt the butter and duck fat together on medium low heat.

Lay down the chicken in the pan and continue to cook on medium heat until you have a nice golden crust. Flip the chicken and repeat. This should take about 4 minutes per side.

Then remove the chicken to a platter and set aside.

Preheat your oven to 375° F convection.

In the residual oil, add the shallots or onions, salt, thyme, and white wine. Cook until the liquid is reduced by about half, or for about 5 minutes.

Then add the demi-glace and the first amount of lemon juice. Return the chicken and its juices to the pan, directly into the sauce.

Cover the pan with foil and pop into the preheated oven for about 25 minutes, or until the chicken reads 175 F using a meat thermometer. Or you can simmer on the stovetop for about 30 minutes.

Then remove the chicken to a serving platter and set aside. Discard the thyme.

Begin to reduce the sauce on medium heat. When it is reduced by about ¼, add the second amount of lemon juice and the cold butter.

Remove from the heat and whisk the sauce so that the butter melts and is incorporated into a silky, glossy sauce.

Finally, stir in the chopped parsley.

Pour the sauce over the chicken. Finish with a dusting of chopped parsley.