In a bowl mix together potatoes, corn flour, onion, sweet corn, carrot, green chilli paste, ginger garlic paste, mixed herbs and salt.
Mix all the ingredients well. Divide into 5 equal portions. Set aside.
In another bowl mash together, kidney beans, black pepper powder, red chilli sauce and salt.
Divide into 5 equal portions. Set aside.
Make a flat tikki with the potato mixture and place the red kidney bean mixture in the center and cover it well to make a flat sealed tikki. Similarly make the other tikkis.
Heat oil in a kadai, deep fry the tikkis till golden brown and crisp.
Remove on absorbent paper.Cut the buns horizontally in two.
Apply butter on both the breads. Place the fried tikki on one bread and cover with the other bread.
Serve immediately with ketchup.