Preheat oven to 400.
Heat a large skillet over medium high heat. Add oil to hot pan with beef or turkey. Season meat with salt and pepper. Brown and crumble meat for 3 or 4 minutes. Add chopped onion to the meat; cook an additional 5 minutes, stirring frequently.
In a second small skillet over medium heat cook butter and flour together 2 minutes. Whisk in consume/water mixture and Worcestershire sauce. Thicken gravy 1 minute. Add gravy to meat mixture; stir in peas and carrots.
Transfer meat and vegetable mixture to an 8x8-inch baking dish coated with cooking spray. Spoon mashed potatoes on top and sprinkle with paprika. Bake for about 35 minutes until the casserole is bubbly and the top is browned.