Whisk curd in a bowl. Add all ingredients of marination mix well.
Add Paneer, capsicum & onions in curd paste.
Gently mix so that the marination coats the paneer, onions and capsicum evenly. cover the bowl & marinate for a minimum of 30 minutes or for 1 hour.
Cut onion, garlic & ginger in pieces. Add 1/4 cup water & cover it. Boil them for 3-4 minutes. Switch off gas.
Once onions cooled. Add cashews & peanuts in Mixer jar and grind them in fine paste. Grind tomatoes & green chillies separately.
Heat Kadhai. Add oil. Add onions paste. Saute until it separates oil in a Kadhai or turns golden brown.
Now add tomato paste. Saute all until leaves oil.
Add kashmiri red chilli powder, turmeric powder, coriander powder, salt, Garam Masala & Kasuri Methi. Saute all for 1 minute. Add 1.5 cup water in it. Let it boil. Add hung curd or milk cream. Stir all. Boil gravy on slow flame.
Meanwhile on another stove Heat pan. Add oil. Place Paneer pieces. Shallow fry paneer cubes on high flame. Flip them & roast on each side.
In same pan drizzle some oil. Place marinated capsicum & onions. Shallow fry them on high flame on each side.
Add fried paneer, capsicum & onions in gravy. Boil them for 2-3 minutes.
Restaurant style Paneer Tikka masala is ready to serve. Garnish with coriander leaves. Serve with butter naan, roti or parantha.