There used to be a little shop in Pigeon Forge, Tennessee called The British Shop. They served teas and lunch. They had a very tasty dish they called Shepherd's Pie. I've looked at lots of recipes for Shepherd's Pie, and none of them seemed to match what they served there. This one I use comes close. Hope you enjoy!
Brown beef well in a 9- or 10-inch iron skillet. Drain any fat off. Stir in gravy mix and the water; bring to boiling. Cook until gravy thickens. Remove from heat.
Arrange thinly sliced onions over top of beef and gravy. Sprinkle well with salt and pepper. Then arrange green beans evenly over all.
Drop mashed potatoes over top of green beans, and spread to edges of pan. Bake for about 25 minutes, until potatoes are browned on top. Remove from oven, sprinkle with grated cheese, and let sit about 5 minutes so cheese slightly melts, before serving.