Heat a large pot over medium to high heat, add the oil, diced onion, minced garlic, and whole cumin seeds. Let it cook until soft.
Then add the canned brown lentils including the brine/water from the can. Add a cup of water, salt, and garam masala. Put the lid on the pot and let it cook for at least 20 minutes.
Use an immulsion blender and blend some of the curry to make it creamier.
Then add the quartered cherry tomatoes and let it cook for another 5 minutes or so. At this point, you can also add more salt or garam masala to taste.
The lentil curry is best served with basmati rice and homemade naan. Enjoy!