Add besan and mustard oil to a pan. Cook on medium heat until lthe roasted flour gives off a lovely aroma. Constantly mix so that it doesn't burn.
Once done, transfer this mixture to a mixing bowl. Let it cool.
To this, add yoghurt, salt, red chilli powder, coriander powder, crushed black pepper, lemon juice, kasuri methi, pav bhaji masala and amchur powder.
Use a whisk to make a lump-free mixture. Add water and mix. Keep it aside.
Heat 1 tbsp oil and 1 tbsp butter in a pan.
On medium heat, add ginger and fry it for about 30 seconds.
Add thinly sliced onions. Fry till they turn translucent.
Add tomatoes and salt. Reduce the heat. Cover with a lid and cook till the tomatoes become mushy.
Add the spice and yoghurt mixture. On medium heat, cook this mixture for about 10 minutes, constantly mixing and stirring with a spatula.
Add chopped green chillies.
Add crumbled paneer. Mix.
Add milk. Mix. Taste and adjust the salt.
Transfer to a serving bowl.
Prepare a tadka, by heating 1 tbsp of oil in a pan. On medium heat, add Kashmir red chilli powder.
Add this to the prepared paneer bhurji. Garnish with fresh coriander leaves and serve.