Paneer and vegetable skewers

INGREDIENTS

• 125ml/4½fl oz Greek-style yoghurt
• small knob fresh ginger
• 2-3 garlic
• , to taste salt
• ½ tsp chilli powder
• 1 tsp garam masala
• 2 tbsp lemon juice
• 2 tbsp vegetable oil
• 1 tbsp gram flour (also called chickpea flour
• 1 tsp cumin
• seeds of 6 green cardamom
• 300g/10½oz paneer
• 1 large onion
• 1 green and 1 red capsicum
• , for greasing oil
• 6 wooden skewers, soaked for an hour
• 2 tbsp butter
• chaat masala (a dried spice mixture available from Asian grocers), to sprinkle