Peel your potatoes and cut into 1/2 to 1 inch cubes.
Boil potato cubes until very soft.
Drain water from potatoes.
Add butter, sour cream, and milk. Whip until creamy. Add salt and pepper.
Thoroughly brown meat in a large skillet.
Dice onion and add to browned meat. Cook 2-3 minutes, or until onions are translucent.
Add flour and stir to coat evenly.
Add garlic, chicken broth, tomato paste, rosemary, and thyme.
Bring to a boil until mixture thickens.
Mix in frozen vegetable and cook for about five minutes (or until the vegetables are crisp, but not soggy).
Fill your tinfoil container about halfway with meat mixture.
Add mashed potatoes, being careful not to disturb the meat mixture too much.
Sprinkle some cheese on top.
Cover with heavy duty foil and crimp the sides tightly.
Place tin foil containers directly on bed of hot coals and cook for about thirty minutes.
About five minutes before your shepherd's pie is cooked, put hot coals on top.
Take off and check that everything is hot. Cook for another 5 - 20 minutes, if needed.