In a flat and wide pan, add oil + butter and sauté tomatoes until soft, next add in the carrots, boiled green peas, capsicum and ginger garlic paste with little salt and add little water may be 1/4 cup and cover and steam cook until they have softened. Stir in-between or add more water to prevent from burning. ( Alternatively you can also pressure cook the veggies and continue with next step.
Once the veggies are cooked, add the boiled potatoes, roughly crumble it with your hand and add it to the veggies. Add 4 tsp of pav bhaji masala , 1 and 1/2 tsp Kashmiri Red chilli powder, Kasuri methi and mix it in the veggies
Add 2 tsp of butter to the veggies, use a potato masher and mash it until all the veggies combine well. Add water about a cup to make it more creamy in consistency.
Cover and cook until all the veggies also have absorbed all the pav bhaji flavour. Check for seasoning, salt and add more if required.
Transfer the cooked veggies to a plate and keep aside.
Use the same pan, add 1/2 of remaining butter and once it melts, add onions and sauté until soft add 2 tsp of pav bhaji masala and 1 and 1/2 tsp of Kashmiri red chilli powder 1/2 of Corinder leaves. Sauté for a few mins until you start to see oil oozing on the sides
Next add the cooked veggies, add the remaining water to loosen the pav bhajji, use the masher to further smoothen it out.
Cover and Simmer 10 more minutes or more until the pav bhajji is runny at the same time thickened and glossy. Finally garnish with some fresh coriander leaves and a generous squeeze of lime juice and butter before serving.
Toast the milk buns or pav buns with butter and serve it hot with Lime or lemon wedges and some finely chopped red onions.