@mismi,
It's pretty much my own invention--you just guess proportions to taste and however many you need to feed.
Prepare seasoned mashed potatoes (salt, pepper, usual dab of butter, a little milk, a few optional chives works well)--fairly stiff. Line casserole dish with potatoes leaving 'well' in the middle. Conserve about 1/4th of the potatoes.
Meanwhile thorough brown lean hamburger seasoned with salt, pepper, a dash of basil (optional). Drain meat well but leave in the skillet. The last minute liberally add worchestershire sauce and heat so the drained browned meat will absorb it. Transfer the seasoned meat to the mashed potato well and cover with the reserved mashed potatoes. Bake in 350 degree oven until potatoes are browned and very slightly crisped on the top - usually 20 minutes or so is sufficient.
Serve with veggies and fruit of choice. Usually turns out pretty good.