Preheat the oven to 350 F (180C), with the oven rack in the middle of the oven.
Pre- cook the potatoes. Heat a large skillet with 1-2 inches of vegetable oil it and add the potato slices. Fry for a few minutes a side, until golden brown but not necessarily cooked through. Set aside on to a paper towel lined plate to cool slightly, and pat off any excess oil.
Layer the kafta in the pan with potatoes, tomatoes, then the onion slices.
Prepare your sauce by whisking together the water, tomato paste, seven spices, and pomegranate molasses. Pour the sauce evenly onto the kafta and vegetable layers. It should be enough sauce to totally submerge the meat mixture and cover the potatoes, some tomato and onion slices may be exposed. If the pan isn't saucy enough, you can add a little extra water.
Cover the pan with aluminum foil, and bake for 45-50 minutes. Uncover, and bake an additional 15-20 minutes, or until meat and vegetables are cooked through (I usually test a little piece of the meat with a fork)