Take 750 gm of Bhetki fillet, cut them into small squares, join 4 squares with a toothpick, and put them in a bowl. (Pro tip: You can make cubes if you get a sizeable chunk of Bhetki fish. However, doing it in my way ensures better marination).
Add 1 tsp of ginger garlic paste and regular table salt to taste. Mix it with each piece very nicely. Keep it aside for 10 to 15 minutes. (Pro tip: Do not add lemon juice for marinating Bhetki fish as it is very soft and will break easily while cooking).
Now take another bowl. Put 2 tbsp of hung curd, 1 tsp of carom seeds (ajwain) after crushing them in your hand, 1.5 tsp of Kashmiri red chili powder, ½ tsp of turmeric powder, 1 tsp of white pepper (shah marich) powder, and 1 tsp of chaat masala powder and ginger garlic paste. (Pro tip: Using ajwain is a must for making fish tikka. If you do not have white pepper powder, you can use regular black pepper powder).
Follow it with 1 tbsp of gram flour (besan), 1 tsp of roasted cumin seeds powder, 1 tsp of dry roasted fenugreek leaves (kasuri methi) after crushing them in your hand, and 1 tbsp of mustard oil. (Pro tip: Besan helps in binding. So, do not skip it).
Mix everything nicely. Keep it aside for 5 minutes to set properly.
Now, coat the fish pieces nicely.
Keep them aside for just 4 to 5 minutes to set properly. (Pro tip: Do not keep the fish pieces in this way for a long time as the salt and curd will release water).
Now, heat a pan (preferably a grill pan) on a high flame. Grease it with 2 tbsp of mustard oil using a brush.
Turn the flame to medium. Put each piece leaving adequate space in between to flip them easily.
Flip them from time to time to fry them nicely on all sides on medium to high flame for about 6 to 7 minutes. Remove them when they turn blackish-brown in color. (Pro tip: Never fry them on a low flame. Also, do not rush. It might leave the raw smell of the ingredients and the fish).
Your tasty and spicy fish tikka is ready to serve. Lay them on a plate and serve them hot with lemon wedges, mint and yogurt chutney, sliced onions, carrot, and beetroot julienne salad.