Grate the Gruyère cheese. Peel and slice the potatoes (about 2-3mm) either by hand or with a mandolin.
Peel and slightly crush the garlic. Grease an ovenproof dish with plenty of butter.
Take a large pan, add the cream, milk, garlic cloves, spices and bring to simmer temperature.
Add the sliced potatoes and simmer for 5 min and continue to stir continuously to stop the potato slices sinking and sticking to the bottom of pan.
Remove the potatoes and layer a third of the potatoes into the greased ovenproof dish flowed by a layer of Gruyère and warm cream. Repeat twice so that you end up with three layers. Pour over the remaining warm cream so that the potatoes are just covered.
Bake for 40-45 minutes or until the potatoes are soft and browned at 190’C.