Blanch fresh spinach in boiling water for 30-45 seconds until wilted, then immediately transfer to ice water to stop cooking.
Drain spinach thoroughly, squeeze out excess water, then blend with tomato and 1/4 cup water until completely smooth. Set aside.
Pat chicken dry, season with salt and turmeric, then sear in hot ghee for 3-4 minutes per side until golden brown. Remove and set aside.
Caramelize diced onion in the same pan for 8-10 minutes until deeply golden, then add garlic, ginger, and all ground spices, cooking for 1-2 minutes until fragrant.
Pour in the spinach puree and let simmer uncovered for 5-7 minutes until the sauce thickens and the raw green smell mellows.
Return seared chicken to the pan, cover, and simmer on medium-low for 15-18 minutes until the chicken is cooked through and tender.
Stir in heavy cream and yogurt (off the heat to prevent curdling), then add crushed kasoori methi and garam masala. Simmer for 2-3 more minutes to meld flavors.
Rest for 2-3 minutes, then ladle into bowls and garnish with fresh cilantro and a drizzle of cream if desired. Serve hot with rice or naan.