Wash and peel the potatoes and slice them very thinly using the wide blade of a grater.
Sprinkle with 1/2 tsp salt and 1/2 tsp white pepper and set aside.
In a large bowl, combine 500ml cream, 100ml milk, 1/2 tsp salt, 1/2 tsp white pepper, thyme leaves from 3 sprigs and 1 tsp ground nutmeg.
Stir and set aside.
Rub the bottom of the baking dish with the cut side of the garlic clove and smear with half of the softened butter.
Stack the potato slices almost vertically, moving along the inner side of the baking dish. Add the pile by pile, using your fingers to support the slices from falling back. Once the first circle is complete, add a stack to the middle.
Pour the cream mixture over.
Use the remaining softened or spreadable butter to brush the edges of the potatoes that stick out.
Bake in pre-heated oven for 45-60 minutes at 200C. Check the doneness by picking out a slice with tongs.
Serve immediately.