Preheat the oven to 200°C, fan 180°C, gas 6. Put the potato wedges on a baking tray, drizzle over 1 tablespoon of the oil and bake for 35 minutes until crisp and golden.
Meanwhile, combine the lamb mince, mint jelly, cumin seeds, egg and breadcrumbs in a large bowl. Season with freshly ground black pepper and shape into 4 burgers. Chill in the fridge for 10 minutes.
Spoon the yogurt into a small bowl and mix in the mint. Season with freshly ground black pepper and set aside.
Brush the burgers with the remaining oil, then cook under the grill for 15-20 minutes, turning once, until cooked through. Meanwhile, toast the burger buns.
Serve the burgers in the toasted buns with a dollop of the minty yogurt sauce, salad and slices of tomato.