Heat the oil in a large skillet over medium-high heat. Add the diced onions and sliced bell peppers. Sauté for 3 minutes until the onions turn translucent and the peppers begin to soften. Stir in the ginger-garlic paste and cook for 1 more minute until fragrant.

Turn the heat down to medium. Push the onions and peppers to the outer edges of the skillet. Sprinkle the garam masala, cumin, coriander, turmeric, chili powder, and salt directly into the empty center of the pan. Let the spices toast in the oil for about 30 seconds until they smell incredibly fragrant.

Lay the whole, thin-sliced chicken breasts flat in the center of the pan, right on top of the toasted spices. Let them cook undisturbed for 3 to 4 minutes until the undersides are beautifully seared and white halfway up the sides.

Flip the chicken breasts over. Immediately scatter the chopped kale leaves all around the pan, mixing them in with the peppers and onions. Pour in 2 tablespoons of water to create a little steam, put a tight-fitting lid on the skillet, and let it cook for 4 minutes. The steam will perfectly tenderize the hearty kale while the chicken finishes cooking.

Remove the lid. Take your wooden spoon or spatula and press down on the chicken breasts—they will be so tender that they easily break apart into rustic, bite-sized pieces right in the pan. Toss everything together for 60 seconds so the rich, thick bhuna spice paste coats every piece of chicken, pepper, and kale.