There are endless permutations of potato gratins and all of them go well with game. This particularly one uses no dairy products and can accompany grilled venison or pigeon breasts.
Preheat the oven to 190°C/375°F/gas 5. Oil the bottom of a gratin dish. Peel and cut the potatoes into 3 mm (⅛ inch) thick. Layer about one-third of the potatoes in the dish. Season well with salt, pepper, half the rosemary, and half the garlic. Sprinkle with 1 tablespoon of olive oil.