• The night before you plan on cooking the chicken, lightly salt both sides of the chicken breasts with kosher salt.
• Rest the salted chicken breasts on a rack on a sheet tray in the fridge overnight.
• The following day, when you are ready to start the dinner-making process, pour the stock into a soup pot and place on the stove.
• Turn heat to medium-high, and reduce the quart of stock (4 cups) down by half, until you have 2 cups of stock remaining.
• While the stock is reducing, remove your chicken breasts from the fridge and let them come closer to room temperature.
• When the stock has reduced by half, set it aside for later.
• *When you are ready to cook the chicken, plan on cooking the chicken breasts in two batches.
• To cook the chicken breasts, place a large saute pan on high heat.
• When the pan is very hot, add half of the vegetable oil.
• When the oil is very hot, reduce the heat to medium and add two of the chicken breasts.
• Sear chicken on both sides, until the chicken meat is golden on the outsides and almost cooked in the center.
• *If using a meat thermometer, remove chicken breasts from the saute pan once they have reached an internal temperature of 150F. Note, the chicken breasts will finish cooking in the sauce later.
• Cook the second two chicken breasts the same way.
• Place the chicken breasts on a rack to cool while you prepare the other ingredients.
• Deglaze your saute pan that you used to cook the chicken with 1 Tbsp of chicken stock, making sure the scrape up any brown bits from the bottom of the pan.
• Add the diced white onion to the pan.
• Cook on medium heat until the onions are translucent, but before they are golden-brown.
• Remove onions from heat.
• Add the mushrooms and 2 Tbsp butter to the saute pan.
• Saute on high heat until the mushrooms are golden-brown.
• Remove mushrooms from heat.

Now, it is time to make the velouté sauce:

• In a separate sauce pot, add the salted butter and all-purpose flour.
• Increase heat to medium while stirring.
• Continue to stir butter and flour mixture together with a rubber spatula, and cook until the mixture smells like toasted flour and begins to turn a very pale golden color, or about 8-10 minutes.
• Slowly whisk in the remaining chicken stock into your butter and flour mixture, making sure that all of the liquid is fully incorporated into the butter and flour.
• Cook the sauce for roughly 5-10 minutes on medium heat, stirring continuously.
• Add the tiny splash of sherry vinegar to the sauce.
• Taste the sauce and adjust for salt and pepper until it tastes fantastic.
• Remove the sauce from the heat and set aside for later.
• In a separate soup pot, add the cut russet potato chunks and cover by 2” with cold water.
• Bring the potatoes to a simmer, and add kosher salt until the water tastes pleasantly salty.
• Boil the potatoes for roughly 20 minutes, or until they are completely tender.
• Drain potatoes in a colander, and return them to the pot.
• Mash the potatoes with a fork or potato masher, and quickly stir in the butter and warm heavy cream until fully incorporated.
• Season the mashed potatoes with kosher salt and freshly-ground black pepper.
• Set the mashed potatoes aside for later.
• Bring a medium-sized pot of salted water to a boil.
• Add the green beans and cook until just barely tender, or about 4-6 minutes.
• Drain green beans and add the 1 Tbsp salted butter. Mix until the butter has evenly coated the cooked beans.
• Taste and season green beans with a sprinkle of salt & freshly-ground black pepper, if desired.
• Add the cooked diced white onions and cooked mushrooms from earlier to the velouté sauce, and bring to a gentle simmer.
• Add the chicken breasts to the velouté sauce and vegetables, and warm them up until the chicken breasts are cooked, or until they reach an internal temperature of 160F.
• Serve plates up with the creamy mashed potatoes, onions, mushrooms, chicken breast, velouté sauce, and green beans.
• Garnish the plates with the finely-sliced fresh parsley and fresh chives.