Start the pressure cooker in sauté mode (high flame for stovetop pressure cooker) and heat 2 tbsp butter/oil in it. Add onions and sauté for 3 minutes.
Add bell pepper and sauté for another 2 minutes. Add tomatoes, pav bhaji masala and salt. Add the ground chili paste. If anything is stuck to the bottom of the pot, scrape it with a spatula.
Add cauliflower, potatoes, carrots, and green peas. Mix well.
Open the pressure cooker and use an immersion blender to coarsely grind the ingredients. You can also use a potato masher to mash the bhaji to the desired consistency.
Change to sauté mode and let the bhaji boil for a minute. Mix in the lime juice. Bhaji is ready to be served.