Step 1: Bring the milk and cream to the boil, add the onions and garlic.. Then turn down to simmer
Step 2: Peel and slice the potatoes. Slices should be about the thickness of a pound coin.
Step 3: Place the potatoes in an oven proof dish, I choose to do a layer of sweet potato at the bottom and then normal potato at the top.
Step 4: Pour on the milk, cream, onion and garlic mixture and cook at 160 degrees for one hour on the middle shelf.