The night before you plan to make your Coq au Vin, submerge your chicken drumsticks and thighs in the red wine with the leeks, diced white onion, diced carrots, diced celery, and kosher salt.
Leave to marinate overnight.
After your chicken has marinated in wine overnight, strain the vegetables and chicken out from the wine, reserving the wine that was used as a marinade in a cooking pot.
Set your vegetables and chicken aside in a bowl. You will notice the chicken exterior has taken on a dark purple color—this is normal and perfect!
Cook your red wine liquid until it has reduced by 1/3 and set aside.
In a small sauce pot, combine the 5 Tbsp salted butter with the ¼ cup all-purpose flour and cook while stirring with a rubber spatula for 10 minutes, or until the mixture has taken on a light golden color.
This cooked butter and flour mixture is your roux, and will be used to thicken your braising liquid later.
In a Dutch oven, heat 2 Tbsp vegetable oil until it is warm and add your drained leeks, onions, carrots, and celery from before.
Cook on medium heat for 5 minutes.
Add your tomato paste and cook for an additional 15 minutes, stirring frequently.
If the vegetable and tomato paste mixture gets too dry, add some chicken stock.
After the tomato paste has cooked and turned a darker red color, add the remaining chicken stock and bring to just below a simmer.
Add your minced garlic, bay leaves, thyme sprigs, and rosemary sprigs turn heat to low.
Dry your chicken thighs off completely using paper towels.
*You are going to quickly sear the outsides of the chicken thighs in piping hot vegetable oil, where it is going to be very dangerous if your chicken is too wet when it goes into the hot pan with vegetable oil. You will also get a better quick sear if your chicken is completely dry before it is added to the pan.
In a large saute pan, heat 2 Tbsp vegetable oil until nearly smoking.
Quickly sear your dried chicken thighs on both sides until the purple exterior has taken on an even darker shade.
*Note, because your chicken marinated in red wine overnight, you aren’t going to see the same “golden-brown” color we are familiar with seeing when searing chicken. The end product is going to be darker, because the marinated chicken is already quite dark before it has been cooked.
After the chicken pieces have been quickly seared on high heat, remove from the heat.
Deglaze your chicken searing pan with some of the braising liquid to remove any fond that is stuck to the pan.
Pour deglazing liquid back into your braising liquid in your Dutch oven.
Add your red wine marinate liquid that was reduced earlier by 1/3 to the braising liquid and bring contents back up to a simmer.
Add your cooked chicken and reduce heat to low.
Cook chicken on low heat, for about 2-2.5 hours, or until the chicken is fork tender and nearly falling off the bone.
While the chicken is cooking, prepare your cooked bacon lardons and set aside to drain on paper towels.
Cook your Bella mushrooms and pearl onions separately in a saute pan with 2 Tbsp of butter for the Bella mushrooms and 2 Tbsp of butter for the pearl onions.
Cook mushrooms and pearl onions separately until tender and set aside for later with the cooked bacon lardons.
After your chicken is fork tender, remove chicken from the cooking liquid.
Whisk in your butter and flour (“roux”) mixture you made earlier into your braising liquid until the roux is fully incorporated and no lumps remain.
*This whisking of the roux into your braising liquid will help thicken your braising liquid, turning it into more of a sauce.
Taste and adjust for salt.
Introduce chicken back to braising liquid.
Serve chicken and braising liquid in large bowls over buttery mashed potatoes, garnished with some of the cooked bacon lardons, Bella mushrooms, and pearl onions from earlier.
Top each bowl with a sprinkle of freshly minced parsley.
This would be great with a green vegetable side, such as buttered green beans with garlic.