Cook the chicken adding pepper pwd, chili pwd, enough salt and 2 cup of water. Keep it aside.
Crush together cooked chicken and onion in a food processor or chop it finely.
Heat oil in a pan, add the crushed chicken and onion, chopped green chili and ginger garlic paste and saute for about 3 - 4 minutes.
To this add garam masala powder and coriander leaves and mix well.
In another pan, heat butter, add 2 tbsp all purpose flour and saute for about 2 - 3 minutes. Slowly add milk and cook till thick stirring continuously. Add pepper powder and salt and mix well. Add this white sauce to the chicken mixture and mix well. Let it cool for some time.
Take small portions, roll it and shape them into croquettes. Roll it in all purpose flour, then in egg whites and then roll it in bread crumbs.
Heat oil in a deep pan and fry these croquettes in medium hot oil. Serve hot with tomato sauce and mayonnaise.