Instructions:

1. Preheat your oven to 400°F (200°C). Grease a casserole dish with butter and set aside.
2. Wash the baby potatoes thoroughly and slice them Hasselback style, making sure not to slice all the way through, leaving the base of the potato intact.
3. Arrange the sliced potatoes standing up in the greased casserole dish, fitting them snugly together. Sprinkle each potato with salt and pepper.
4. In a small saucepan, combine the heavy cream, minced garlic, and thyme leaves. Gently heat the mixture until it is hot but not boiling. Pour the warm cream mixture over the potatoes, ensuring it seeps into the slices.
5. Sprinkle the cheddar cheese evenly across the top of the potatoes, followed by the Parmesan cheese.
6. Cover the dish with aluminum foil and bake in the preheated oven for about 40 minutes.
7. After 40 minutes, remove the foil and return the casserole to the oven to bake for an additional 20-25 minutes, or until the tops are golden brown and crisp.

8. Once done, remove the casserole from the oven and let it rest for a few minutes. Garnish with an extra sprinkle of fresh thyme leaves before serving. Enjoy!