I use as many potatoes as I think will fill the bowl. I then add in a few sweet potato slices for some colour and a different flavour.
I mix together some milk, crushed garlic, a chicken stock cube and some Italian herbs until I have enough liquid ( I add water if necessary) to splash some around each layer as I am putting it all together.
I sprinkle the top with some mozzarella and a handful of Italian herbs and put it into the oven on 180 c for about 45 minutes. I poke it with a knife to make sure it is fully cooked.