Bhaji burger

Name: Bhaji burger
Prep time: 30 min
Cook time: 20 min
Total time: 50 min
Cuisine: Indian
Ingredients: 400g lamb mince; 2 tbsp tandoori paste; 1 tsp cumin seeds; ½ cucumber; 150g pot plain yogurt; ½ small pack mint , leaves chopped; 100g plain flour; 1 tbsp garam masala; 1 tsp bicarbonate of soda; 1 onion , halved and finely sliced; 3 tbsp sunflower oil; 3 burger buns (we used brioche buns), toasted; a few lettuce leaves; red onion , thinly sliced; mango chutney