Fish Tikka with Ajwain and Mustard Oil Marinade

Ingredients

• 800 g boneless firm white fish fillets (such as rahu, sole or mahi mahi), cut into 4 cm cubes
• 1 tsp salt, for the first seasoning
• 2 tbsp lemon juice
• ½ cup thick plain yogurt, hung or strained if watery
• 1 tbsp ginger-garlic paste
• 1 tbsp Kashmiri red chilli powder
• 1 tsp red chilli powder, or to taste
• 1 tsp ground coriander
• 1 tsp ground cumin
• ½ tsp turmeric powder
• ½ tsp ajwain (carom seeds), lightly crushed
• 1 tsp garam masala
• 1 tbsp chickpea flour (besan), dry roasted for 1 minute in a pan
• 1 tbsp mustard oil or vegetable oil
• 1 tsp salt, for the marinade, or to taste
• 1 green capsicum, cut into 3 cm squares
• 1 large onion, cut into 3 cm wedges with layers separated
• 2 tbsp oil, for basting
• 1 tsp chaat masala, for finishing
• 1 lemon, cut into wedges, to serve
• 2 tbsp fresh coriander, chopped

Instructions

1. Pat the fish cubes dry with kitchen paper. Put them in a large bowl and toss with 1 tsp salt and the lemon juice. Leave for 10 minutes; this seasons the flesh and firms it slightly.
2. While the fish rests, whisk together the yogurt, ginger-garlic paste, both chilli powders, coriander, cumin, turmeric, ajwain, garam masala, roasted besan, mustard oil and 1 tsp salt in a separate bowl until smooth and thick.
3. Drain any liquid from the fish, then fold the fish gently into the marinade so every piece is coated. Cover and refrigerate for at least 30 minutes and up to 2 hours; longer can make the fish mushy.
4. About 15 minutes before cooking, heat the grill to medium-high, or heat the oven to 240°C with a rack over a tray, or heat a grill pan over medium-high heat. Brush the grill bars, rack or pan with oil so the fish does not stick.
5. Thread the fish onto skewers, alternating with pieces of capsicum and onion. Leave a small gap between the pieces so they cook evenly, and brush lightly with oil.
6. Grill for 4 minutes without moving, until the underside is browned and releases easily. Turn carefully and cook 3 to 4 minutes more, brushing with a little oil. Repeat on the remaining sides if the skewers are square.
7. Check that the fish is opaque and flakes easily, or reads 63°C in the thickest piece. The edges should be lightly charred. In the oven, allow 10 to 12 minutes in total, turning once.
8. Rest the skewers for 2 minutes, then sprinkle with chaat masala and coriander. Serve hot with lemon wedges.

Tips

• Use a firm fish. Delicate fillets break apart on skewers; if the fish is soft, grill it in a lightly oiled basket or on foil.
• Thick, well-drained yogurt is important. A watery marinade steams the fish instead of charring it.
• Do not marinate for more than 2 hours, as the lemon and salt will start to break down the flesh.
• Turn only once the fish releases from the grill; if it sticks, give it another minute.