Wash the thyme, shake dry and pluck the leaves. Peel and chop the garlic. Peel and wash the potatoes and slice or slice them thinly. Peel, wash and slice beetroot.
Potatoes, beetroot, garlic, thyme, oil, good 1⁄2 Mix TL salt, pepper and 1 pinch of sugar. Spread into a greased casserole dish.
Grate the cheese and sprinkle over it. Close the mould with aluminium foil. Bake in the preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer) for approx. 50 minutes. Remove foil and sprinkle pumpkin seeds over the gratin.
Bake open for another 20 minutes until golden brown.