Preheat oven to 400°F.
In a small saucepan add cream, garlic, nutmeg and bring to a simmer over medium heat, about 6 minutes. Remove from heat.
In a medium bowl, mix the 3 cheeses together, until well combined. Separate ½ cup of mixed cheese aside.
Using a mandolin slice potatoes ⅛ inch thick and immediate place in a large bowl of cold water. Pat completely dry using a paper towel.
In a 10 inch skillet, arrange potatoes in a single layer at the bottom, then top with ¼ cup of cheese. Repeat until you achieve 3 layers of potatoes and cheese until everything is used up (reserve the ½ cup that was aside earlier for the top). Then pour cream mixture over and sprinkle with remaining ½ cup cheese.
Shimmy the skillet to ensure cream is evenly distributed. Bake in the oven for an hour until potatoes are fully cooked.
Remove from oven and sprinkle with remaining cheese. Then use a BZ4500HS Bernzomatic torch to char the top until golden brown. Sprinkle with thyme leaves and serve immediately.