Prepare the Potatoes:
Place the potato slices in a large bowl of cold water to prevent browning. Drain and pat them dry with a paper towel.
Make the Cream Mixture:
In a saucepan, combine the heavy cream, whole milk, minced garlic, dried thyme, butter, salt, and black pepper. Heat the mixture over medium heat until it’s warmed through and the butter is melted. Do not let it boil.
Layer the Potatoes:
Grease a baking dish with butter or cooking spray. Place a layer of potato slices on the bottom of the dish, slightly overlapping them.