Heat oil in a large skillet . Brown chicken on medium high heat for 2-3 minutes per side and place in a 9x13 pan that has been sprayed with non-stick cooking spray. This can be done in two batches if the skillet isn’t large enough to fit all the chicken at once.
Pour chicken broth and cooking sherry into skillet and heat until boiling. Boil for 2 minutes, stirring to lift all the brown bits from the bottom of the pan. Stir in salt, pepper, and poultry seasoning.
In a small bowl, whisk cornstarch and water. Whisk cornstarch mixture into boiling broth mixture. Cook for 2 minutes or until starting to thicken. Remove from heat and set aside.
Sprinkle chopped onion, carrots, celery, and frozen peas evenly over chicken.
Pour broth mixture over the chicken and cover pan with foil. Cook for 45 minutes.
While chicken is cooking, prepare the biscuits. In a medium bowl, combine flour, baking powder, and salt. Cut in butter with a pastry blender until mixture resembles coarse crumbs. Stir in milk until dough begins to hold together. Move dough to a counter or cutting board and knead 4-5 times. Do not overwork dough. Form dough into a ball and divide into 8 equal pieces. Form each piece into a circle and flatten slightly.
When timer rings for chicken, remove from oven and turn oven to 425℉. Place biscuits on top of chicken and return to oven, uncovered, for 15-20 minutes or until biscuits have started to turn golden brown. Sprinkle with chopped parsley and serve immediately.
If you’d like to save time, you can use a biscuit mix instead of making your own.
Don’t worry if the dish seems too watery after you take it out of the oven the first time. It will thicken up more as the biscuits cook.