Clean the chicken and cut it into small cubes.
Apply a mixture of lemon juice, ginger garlic paste and salt to the chicken and keep it aside for half an hour.
Meanwhile, remove the whey from the curd by hanging it in a muslin cloth for 15 minutes.
To this curd, add Tandoori Tikka Masala powder and mustard oil. Mix well.
Apply this marinade onto the chicken pieces and refrigerate for 4 hours.
Preheat a oven to 180°C (fan forced to 160°C). Place the chicken fillets on a rack with drip tray underneath and slide onto the middle shelf of the oven..
Cook for 15 minutes, and then brown under top heat for 5 minutes on either side.
Place chicken tikkas in a bowl and sprinkle with chat masala and lemon juice. Serve on a warm plate, garnished with onion rings and lemon wedges.