Combine one teaspoon dried parsley, paprika, onion powder, salt, pepper, mustard powder and garlic powder in a small bowl.
Drizzle one tablespoon of oil on the chicken breasts and sprinkle with the seasoning mixture. Rub it on both sides of the breasts.
Turn on the Instant Pot to the sauté function and add one tablespoon of oil. Add the breasts and cook 2 to 3 minutes per side, or until browned. Turn off the instant pot.
Add chicken stock and remaining teaspoon of dried parsley to the pot and give it a quick stir.
Place the lid on the instant pot and lock it into place. Seal the valve and pressure cook on high for 8 minutes. Let pressure naturally release for 5 minutes before switching the valve to the “venting” position and manually releasing any remaining pressure. Unlock and remove the lid.
Transfer chicken to a plate and cover to keep warm.
Turn the instant pot to the saute setting. Whisk together water and cornstarch and add to the pot, whisking to combine. Add chicken bouillon or better than bouillon base if using now. Cook for 7 to 10 minutes, stirring frequently, until the gravy thickens to your liking. Season with salt and pepper.
Stir in butter and heavy cream if using.
Slice chicken breasts and serve gravy over chicken breasts.