Step 1: 1. Boil and then mash the potatoes (using milk for creamier taste)
Step 2: 2. place a layer of mash potato on the bottom of a casserole dish, then sprinkle a layer of cheese, then another layer of potato and finally a thick layer of cheese n the top.
Step 3: 3. Place under the grill until cheese starts to melt and then add tomato and onion to the top.
Step 4: 4. Place back under the grill until the cheese is golden brown.