Preheat your oven to 375°F.
Grease a 9x13-inch baking dish with butter.
In a large bowl, combine the heavy cream, milk, salt, black pepper, paprika, and thyme. Whisk until well mixed.
Layer half of the sliced potatoes in the bottom of the prepared baking dish.
Sprinkle half of the chopped onion and minced garlic over the potatoes.
Pour half of the cream mixture over the layer.
Sprinkle half of the shredded cheese on top.
Repeat the layering process with the remaining potatoes, onions, garlic, cream mixture, and cheese.
Cover the baking dish with aluminum foil and bake for 45 minutes.
Remove the foil and bake for an additional 15-20 minutes, or until the potatoes are tender and the top is golden brown.
Let the dish cool for about 10 minutes before serving.