
Preheat the oven to 425 degrees
Cut the potatoes into slices or cubes and boil them for about 12 minutes. They are done when they are soft and a fork can easily poke them.
Drain potatoes and add butter and seasoning. Mash potatoes and set aside
In skillet cook the beef then, add the onion, carrots, and mushrooms (add any frozen veggies here, canned won't need this). Sauté for about 8-10 minutes just make sure the carrots are soft.
Add the seasonings and the tomato sauce to the mixture, pour in any not added veggies, and stir.
If baking in same skillet, level out the meat and veggies. If not, pour mixture into a baking dish. Then top with mashed potatoes. Spread over meat and veggies to create an even potato layer.
Bake for about 15-20 minutes. This is a wide gap but it has a lot to do with how brown you want your top layer to be. I usually do about 18 minutes
Pull out of the oven and let sit for a few minutes. Then dish as you would like.