Soak soya chunks in warm milk for an hour. Drain and put them in a mixer.
Add salt and grind. Transfer into a bowl. Add chicken mince, salt, green chillies, coriander leaves and finely chopped onion and mix well.
Heat oil in a non-stick pan. Dampen your hands, take a portion of the mixture and shape into a tikki slightly bigger in circumference than the burger bun.
Shallow fry till both sides are equally golden brown.
Slice the burger bun into two and roast them in the pan along with the tikkis.
Spread some mustard paste on each half of the bun and then spread some tomato ketchup.Keep lettuce leaves over each half. On one half place some tomato roundels and onion rings.
Place the chicken tikki on the other half. Sprinkle some freshly crushed peppercorns and cover with the other half of the bun. Press lightly. Serve immediately.