Take 7 large pieces of Bhetki fillets on a plate and add ½ tsp of regular table salt, ½ tsp of black pepper powder, and ½ tsp of ginger garlic paste to it. (Pro tip: I prefer large pieces. You may cut them if you want).
Then, use a grater to put ¼ tsp of lemon zest (Gondhoraj). (Pro tip: Make sure that you do not grate the white potion of the lemon skin. This will make the fries taste bitter).
Next, squeeze about 1 tsp of fresh lemon juice.
Mix them. Keep aside for 10 to 15 minutes for everything to set properly. (Pro tip: Bhetki fish does not need hours of marination like chicken or mutton).
In the meantime, take a bowl and make the batter with ½ cup (100 gm) of refined wheat flour (maida), 4 tbsp (50 gm) of corn flour, ½ tsp of baking powder, ¼ tsp of baking soda, ¼ tsp of black pepper powder, salt to taste, and 2 tbsp of melted butter. Mix them nicely.
Now, add 8 pieces of ice cubes and 2 tbsp of normal water to it. Let them melt. Mix them. (Pro tip: If you do not have ice cubes at home, use chilled water. Do not use a lot of water. You will need a batter with a thick consistency or else it will not stick to the fish pieces.).
Add lemon zest and juice.
Mix them. Check consistency. (Pro tip: You may add one egg first and then a little bit of water to the batter if you want at this point, though I am not since I am allergic to eggs).
Now, heat an adequate amount of refined oil in a kadai on a high flame. Put a drop of batter in it to check whether it floats. Reduce the flame to medium as it is sufficiently hot.
Coat each fish fillet with the batter.
Release it gently in the hot oil.
Fry it, flipping occasionally. Remove when golden brown.
Your tasty and spicy homemade fish batter fries are ready. Lay it on a plate and serve it hot with mango (aam) kasundi and tomato sauce.