Preheat the oven to 400°F (200°C). Slice the tops off the garlic heads, drizzle with olive oil, wrap in foil and roast for 30-35 minutes until soft.

In a mixing bowl, combine heavy cream, whole milk, mashed roasted garlic, salt, black pepper, thyme, and paprika. Whisk until creamy.

Layer half of the sliced Yukon Gold potatoes in a greased baking dish, pour half of the creamy sauce over them, and sprinkle half of both cheeses.

Repeat layering with remaining potatoes, sauce, and cheeses for a second layer.

Cover with foil and bake for 45 minutes. Remove foil and bake uncovered for an additional 20-25 minutes.

Let the dish sit for 10 minutes before serving. Garnish with chopped parsley.