Clean and slice mushrooms. Mince 3 cloves of garlic and 2 tablespoons of parsley.
Turn Instant Pot to saute setting. Pat dry chicken thighs and season evenly with 1 1/2 teaspoons of kosher salt and 1/2 tsp of black pepper on both sides. Coat the chicken thighs in flour and shake off excess.
After the pot is hot (about 5 minutes), add 2 tablespoons of olive to Instant Pot and sear chicken for 1-2 minutes per side. Work in batches and do not crowd the chicken. Place all the chicken on a plate and set aside.
Add 2 tablespoons of butter to the Instant Pot and saute the sliced mushrooms for 5 minutes, then add the garlic and cook for 2 more minutes.
Add the Marsala wine and chicken stock to the Instant Pot. Scrape bottom of the pan with a wooden spoon to dislodge the flavor bits. Add the chicken thighs on top of the mushrooms and close lid.
Set valve to sealing position and cook on high pressure for 8 minutes. When finished let Instant Pot naturally release for 5 minutes, then turn the valve to vent position.
Open lid, remove chicken and cover with foil. If a thicker sauce is desired, mix 1 tablespoon of corn starch with 2 tablespoons of water and add to the sauce. Cook on saute for 3-5 minutes until the desired thickness is achieved. If still too loose just cook for a few more minutes.
Pour sauce over chicken thighs and sprinkle with parsley. Enjoy!
Searing the chicken thighs initially is an important step to increase flavor. Drying the thighs and not overcrowding when searing will help with this process.
Marsala was used but any type of wine is fine. Dry white wines such as Pinot Grigio or Chardonnay work well. If opting for no wine, just use 1 1/4 cups of chicken stock for the recipe.
Only 1 1/2 teaspoons of salt were used. Adjust to personal tastes before serving.
Finishing with cornstarch is optional and will result in a thicker sauce.