1 Little Gem lettuce, finely sliced
2 tbsp fresh coriander leaves
1 garlic clove, peeled and chopped
2.5cm/1in piece fresh ginger, peeled and chopped
2 tsp lemon juice
½ small onion, roughly chopped
½ onion, finely sliced
¼ tsp freshly ground black pepper
½ tsp red chilli powder, or to taste
1 tsp ground coriander
½ tsp ground fennel seeds
2 tsp each garam masala and ground cumin
1 tsp salt, or to taste
1 tbsp vegetable oil
2 tbsp melted butter, for basting
150ml/5fl oz Greek-style yoghurt
100ml/3½fl oz green chutney, mixed with 3 tbsp yoghurt, to serve
400g/14oz lamb (leg meat is ideal), bones removed, cut into 2cm/1in cubes and pierced with a fork
5 ready-made flour tortillas, wrapped in foil and placed in the oven for the last five minutes of cooking