Makes 2 dishes ...so divide the ingredients in 2.Wash the potato well. Slice potato thinly. I left the skin on for a more rustic feel. You can peel if you like.Sprinkle some olive oil over the slices. Season with onion powder, salt and pepper. Butter gratin dish well and layer potato slices slightly overlapping the slices. You may do 3-4 layers. Dot with small pieces of butter and drizzle some olive oil. Bake in a preheated oven at 425-450 (I used my toaster oven at 450) till potatoes are cooked through about 20 minutes. They should be a bit crispy...so adjust the time. Watch so that they don't burn.Take out of oven and sprinkle some cheese. Add sliced yellow squash and sprinkle a bit of cheese.Add tomato slices, onion and a bit more of the cheese.Sprinkle with some breadcrumbs. Drizzle with some olive oil and sprinkle with basil. Return to the oven and bake till golden brown 15-20 minutes.