Thaw the frozen biscuit dough ahead of time.
Place a piece of parchment paper on the counter and place biscuit dough on top. Add another sheet of parchment and roll out with the rolling pin until they are thin and wide enough to fill the casserole dish. Place inside and bake at 400 degrees for about 10 minutes. Remove and set aside.
Melt the butter with the olive oil in the casserole dish, and place the chicken in the dish. Sprinkle with salt, seasoned salt, and pepper and garlic bread seasoning.
Bake the chicken at 400 degrees for about 45 minutes, or until the juices run clear when pierced with a fork, and it's no longer pink in the middle.
While the chicken is baking, rinse and chop the potatoes, carrots, celery, and onion, and place them in a large bowl with the peas, add the garlic and set aside until time to bake.
When chicken is done, remove from oven and let rest. Then pull the breasts off the chicken and dice them.
Return them to the casserole dish, add chicken stock and the vegetable mixture. Add brown sugar and corn starch and stir.
Place in the oven for 30 - 45 minutes, stirring occasionally, until the vegetables are tender, and the gravy has thickened. When the chicken/vegetables are done, place the baked biscuits on top.