Preheat oven to 375 degrees. Grease a 9 x 13 pan or casserole dish with your oil of choice. Next, wash, peel, and slice potatoes in 1/4-1/2 inch thick rounds. (like you would for scalloped potatoes) Slice your onion in rings or chunks, and cut 1/2 green pepper in large chunks. Next, place sliced potatoes, onion, and green pepper in your baking dish. Sprinkle 1/2 tsp of Rosemary on vegetables; along with garlic powder, salt & pepper. With your hands or a spoon, toss these vegetables all up so that the seasonings and oil get incorporated. Try and make sure all potatoes are spread evenly on the bottom. It is ok if they are overlapping a little bit. You just don't want a large pile of potatoes in an area or they won't cook properly.
Add 1/3 cup water to potatoes. Next, season Ham steaks with the other 1/2 tsp Rosemary, garlic powder, salt, and pepper. Lay them over the potato mixture in the pan. Place foil over the pan and bake for 20 min with foil. After 20 min, remove foil and bake for another 30-35 minutes. This time really depends on the thickness of your ham steaks. Also, check your potatoes and make sure they are done, by using a fork to check if they are tender. (Picture is Raw Ham before it's cooked)
Picture after being cooked
