Blend chopped tomatoes in a blender. Set aside. Otherwise, use crushed tomatoes per ingredient above.
Place a pan on low heat. Add in all dry spices (poppy seeds, coriander seeds, fennel seeds, cumin seeds, peppercorn, cardamom, cloves, cinnamon, dried red chilies) and dry roast on the pan for 5-6 minutes until fragrant. Be sure to not let spices burn - make sure you move the spices around on the pan constantly.
Add in shredded coconut once spices are fragrant.
Transfer everything to a blender with 1/4 cup water and blend until paste forms. This is your Chettinad masala paste.
On a separate pan on medium heat, add oil and onions and saute until cooked down.
Add in curry leaves, and then tomatoes, salt, and turmeric and continue to saute.
Add in the masala paste and saute more until well combined. You should have a saucy curry at this point.
Add in paneer cubes and mix well with curry sauce. Let everything heat through well.
Taste and adjust salt and spice as needed.
Serve immediately and enjoy!