Preheat oven to 375°F. Grease a 9x13-inch baking dish with butter or nonstick spray.
Mix the two cheese types together to create a blend.
In a large pot, combine heavy cream, whole milk, garlic powder, dried thyme, dried oregano, onion powder, and black pepper.
Add the sliced potatoes to the pot and bring to a simmer. Cook until potatoes are just tender, 7-10 minutes.
Layer half of the potatoes in the prepared baking dish. Sprinkle with half of the cheese. Repeat with the remaining potatoes and pour the milk mixture from the pot over them.
Sprinkle on the remaining cheese, cover the dish with foil, and bake for 35 minutes.
Remove the foil and bake for an additional 20-30 minutes, until the top is golden brown and bubbly.
Garnish with fresh herbs when serving.