Peel and cut potatoes, put into pan of water, and boil until done (the smaller you cut them the sooner they will get done). Preheat oven 350 degrees F.
Peel and dice carrots and onion. Put hamburger, carrots and onion in skillet and cook until hamburger is no longer pink and carrots are tender.
Bring 2 cups water to boil and add bouillon and bring back to boil. Add some cornstarch to cold water in a cup. Mix into boiling bouillon water until gravy like mixture is made, then remove from heat and let stand.
When hamburger is done, mix gravy into skillet. Add can of corn to hamburger mixture and stir. Drain potatoes and mash with butter and milk.
Put hamburger into cake baking glass or metal. Top with potatoes, spread evenly. Bake for 1/2 an hour to 45 minutes or until potatoes are browning on top and gravy is boiling on the sides.