Preheat your oven to 400°F (200°C).

Roast the garlic by cutting the top off a head, drizzling with olive oil, wrapping in foil, and baking for 30–35 minutes until soft and golden brown.

Prepare the cream mixture by combining heavy cream, whole milk, mashed roasted garlic, salt, black pepper, thyme, and paprika in a mixing bowl. Whisk until smooth.

Layer half of the sliced Yukon Gold potatoes in a greased baking dish, pour half of the cream mixture over, and sprinkle half of the Swiss and Cheddar cheeses on top.

Repeat the layering with the remaining sliced potatoes, cream mixture, and cheeses.

Cover the dish with aluminum foil and bake in the oven for 45 minutes.

Remove foil and bake uncovered for an additional 20–25 minutes until the top is golden brown and bubbly.

Let the dish rest for about 10 minutes before serving, garnished with freshly chopped parsley.