Preheat oven (electric cooker: 225 °C/circulating air: 200 °C/gas: see manufacturer). Clean potatoes thoroughly with the vegetable brush, wash and cut in half lengthwise. Wash oregano, shake dry and pluck the leaves.
Wash the garlic. Wash lemon hot, dab dry and cut in half. Squeeze half, cut the rest into slices. Mix potatoes with lemon juice, oil, half of oregano, garlic, about 1 tsp salt and pepper.
Place the potatoes in the middle of four pieces of baking paper. Take the paper all around the filling and close it. Place the packet on a baking tray. Bake in a hot oven for about 40 minutes. Serve with lemon wedges and the rest oregano.