Place the potatoes in a large saucepan and add the cream and milk. Gently stir to make sure the potatoes are covered wth the cream mixture. Submerse the thyme and garlic, keep an eye on the garlic as you will be removing them later.

Bring to a simmer and cook gently for 5 min. or until just cooked, but not falling apart. Preheat oven to 375F. Remove the thyme and garlic from the milk and discard.

Butter a large casserole dish. Remove half of the potatoes with a slotted spoon and place in the casserole dish. Generously salt and lightly pepper. Scatter 1 cup of the gruyere on the potatoes. Pour half the cream mixture on the potatoes. Top with the remaining potatoes, generously salt and lightly pepper again. Pour on the remaining cream mixture. Top with the remaining cheese. Bake for 30 min. or until lightly browned and bubbly. Freshly grate nutmeg on top and serve.