To make the patty, add cooked chickpeas in a food processor and pulse a few times till coarsely ground.
In a large bowl, mix together all the ingredients from chickpeas to salt listed under burger patty (leave aside flour, milk and breadcrumbs). Taste to adjust seasoning as required.
Heat oil in a non stick pan.
In three different bowls, add flour, milk and breadcrumbs.
Take ½ cup chickpea mixture, and form into a burger patty. Dust it with flour first , dip it lightly in milk and coat it quickly with bread crumbs.
Slide the patties in oil, and cook for 10 minutes on each side till golden brown and cooked through.
Grind all the ingredients under avocado mint chutney to make a smooth paste. Add a little water if required.
To assemble the burgers, slice the buns in half. Layer with lettuce, place the patty and top with the avocado mint chutney and onions. Don't forget the ketchup :)