Step 1

Preheat oven to 350 degrees F. Coat an 8-inch square baking dish with cooking spray.

Step 2

In a large bowl, combine all ingredients except mashed potatoes. Place mixture in prepared baking dish and bake 35 minutes. Remove from oven, drain off any fat, and evenly spread mashed potatoes over top.

Step 3

Return casserole to oven and cook 25 to 30 more minutes, or until no pink remains in beef and potatoes are hot.