Begin by placing your soaked cashews (or raw ones if you're short on time) into a blender with the Greek yogurt. Add just 2 tablespoons of water if needed. Blend until you have a completely smooth, pourable consistency—this should take about 60-90 seconds. There shouldn't be any visible pieces. Now, in a large bowl, combine your ginger-garlic paste, lemon juice, black pepper powder, garam masala, chaat masala, crushed fenugreek, and salt. Pour the cashew-yogurt blend into this bowl and whisk everything together until fully incorporated. The mixture should look creamy and aromatic, with visible spice flecks throughout.

Add your chicken pieces to the marinade, ensuring every piece is thoroughly coated. This is where patience becomes your ingredient. Cover and refrigerate for a minimum of 2 hours, ideally overnight. The yogurt's lactic acid is working to tenderize the chicken, while the spices penetrate into the meat. If you're in a rush, even 45 minutes helps, but the full 2-hour window gives you noticeably better results.

While the chicken marinates, finely chop your onion into small, even pieces—this helps them cook evenly and distribute throughout the sauce. Mince your green chilies, removing seeds if you prefer less heat. Chop your mint and cilantro fresh, just before cooking. Don't do this too early; fresh herbs lose their brightness if cut and exposed to air for too long.

Heat your ghee in a large, heavy-bottomed pan or kadai over medium-high heat. Once it's shimmering and fragrant (about 1-2 minutes), add your chopped onions and green chilies. Stir occasionally, cooking for approximately 2 to 3 minutes, until the onions are translucent and just beginning to soften. You're not looking for deep caramelization here—just gentle cooking to release their sweet notes.

Using a slotted spoon, carefully transfer the chicken pieces from the marinade into the pan with the cooked onions, leaving most of the marinade behind in the bowl. This is important—you'll use that remaining sauce later. Stir the chicken pieces to distribute them evenly, and let them cook undisturbed for about 2 minutes to develop some color. Now, stir and cook for another 3 to 4 minutes, turning pieces occasionally. The chicken doesn't need to be fully cooked at this point; you're creating texture and flavor through contact with the hot pan. You'll notice the pieces taking on a light golden tinge in spots.

Pour the remaining marinade from your bowl into the pan with the chicken. Stir everything together, making sure nothing sticks to the bottom. Bring the mixture to a gentle boil—you'll see it begin to bubble around the edges. Once boiling, reduce heat to medium-low, cover with a lid, and simmer for 10 minutes. During this time, the chicken will finish cooking and absorb the spiced yogurt sauce. The sauce will thicken slightly as it simmers. Check once during cooking to stir gently, ensuring even cooking.

After 10 minutes of simmering, the chicken should be completely tender and cooked through (165°F internal temperature if you're using a meat thermometer). Stir in your heavy cream or coconut milk, incorporating it fully. Taste the dish now—this is your moment to adjust seasoning. Add a pinch more salt if needed, or a light drizzle of lemon juice if it needs brightness. If the dish tastes slightly flat or the spices feel muted, this is where that ½ teaspoon of sugar comes in—it's not about sweetness, but about rounding out the edges and allowing the spices to sing. Add it, stir, and taste again.

Cover the pan again and let everything cook together on low heat for 2 more minutes. Fold in your freshly chopped mint and cilantro just before serving—this preserves their bright, fresh flavor that would otherwise fade if cooked too long.