Preheat oven to 350F, and get out a large baking dish or roasting pan, with lid. (Roughly 14-16 inches at its longest point)
Place a thawed Celebration Roast inside of the dish, then place all of the vegetables around it, mixing them up so each on is evenly distributed. Pour water into baking dish, then sprinkle salt and pepper over veggies.
Cover dish and bake for 30 minutes. Carefully, remove baking dish from oven, and using a baster, get as much liquid out of the bottom and put it into a measure cup.
Spray a thin coating of cooking oil over the roast and veggies, then bake uncovered for an additional 20-30 minutes, and move onto the gravy. Once the roast has reached at least 165F inside, it is done.
You should have around 1 cup of liquid from the baking dish, pour enough water into the measuring cup to make it two cups of liquid. In a small sauce pan, over medium heat, place liquid and mushroom gravy packet. Bring to a simmer, whisking regularly.
Once gravy has become very smooth and has thickened, season it with additional salt and pepper, if you feel it needs it. Pour into a gravy boat, or bowl, for serving.
Serve roast as is, cutting 8 thick or 16 thin slices, for roughly 8 equal servings. Enjoy!