Chop the onion (if using) and put it in the Instant Pot.
Cut the chicken into 1-2 inch cubes and place the cubes on the onions. Season lightly with salt and pepper.
Cut the potatoes into 1 -2 inch cubes and scatter them over the chicken pieces.
Slice the carrots and celery (if using) into 1/2-inch pieces and add them to the pot.
Sprinkle with the rosemary and thyme (or your choice of seasoning) and add the chicken stock. Place the bay leaf on top of the mixture.
Place the lid on the pot and close the pressure valve. Cook on HIGH pressure for 4 minutes. Allow natural pressure release for at least 15 minutes.
In a saucepan over medium heat, melt the 6 tablespoons of butter. Add 1/2 cup of flour and cook for 4 to 5 minutes, stirring constantly, until a light-medium brown color is achieved. Browning will develop the flavor.
Add the heavy cream and peas or green beans and season to taste with salt and pepper. Continue cooking until hot and vegetables are warmed through.
Stir the roux mixture into the chicken filling mixture in the Instant Pot. Stir to blend and cook for about 2 minutes, or until the liquids are thickened. Taste and adjust seasonings. Remove the bay leaf.

Instant Pot Recipes