Preheat oven to 400°F. Spray a large casserole dish with nonstick cooking spray.
Cook the On-Cor Gravy & Sliced White Meat Turkey in the microwave according to package directions. Let stand 1 to 2 minutes before removing with oven mitts from microwave.
Remove the turkey from the gravy and slice into bite-size pieces.
Place stuffing into the bottom of the prepared casserole dish, layer on the turkey and then the peas.
Spoon 2/3 cup of the gravy over the stuffing, turkey and peas. Reserve the remaining gravy for serving.
Spread mashed potatoes over the turkey.
Bake in preheated oven for 30 minutes or until the potatoes begin to lightly brown.