Take all the vegetables. Wash them and cut them into small pieces.
Transfer chopped potato, cauliflower, peas and carrot in a pressure cooker. Add 1/2 cup water and salt to it.
Close the cooker and cook on medium flame till 2 whistles.
Turn off the flame and open the lid after 5-7 minutes.
Mash all the boiled veggies gently.
In a pan separately, heat some oil and butter together on a medium flame.
Add ginger garlic paste and onions and cook till onions become transparent.
Now add capsicum, tomatoes and salt.
Cook until capsicum and tomatoes become soft.
Add red chilli powder, turmeric powder, cumin powder, coriander powder and pav bhaji masala.
Stir and cook for a minute.
Mix 3/4 cup water in it and cook for 3-4 minutes.
Add boiled and mashed vegetables and lemon juice.
Mix well and cook for 5 minutes. Turn off the flame. Bhaji is now ready.
For the buns, Heat tava and shallow fry the buns using butter till it becomes light brown in colour.
Garnish bhaji with coriander and butter and it is ready to be served with the buns.