Mix garlic, ginger, turmeric, garam masala, coriander, and cumin in a small bowl.
Whisk 1 cup of the full fat coconut milk, salt, and half of spice mixture in a medium bowl. Add this mixture to a gallon plastic bag (or storage container of choice), add chicken, and ensure it’s fully submerged in the mixture. Cover and chill 4-6 hours. Cover and chill remaining spice mixture.
Heat ghee in a large pot over medium heat. Add onion, tomato paste, cardamom, and red pepper flakes. Stir often for 5 minutes, until the onion becomes soft. Add remaining half of spice mixture and cook, continuing to stir, about 4 minutes.
Add diced tomatoes with juices. Bring to a boil, then simmer, stirring often until sauce thickens, 8-10 minutes.
Add the entire sauce that’s in the pot to a blender. Add remaining 2 cups coconut milk and chopped cilantro. Blend until smooth.
Return sauce back to the pot and add chicken and remaining marinade. Coat the chicken in the sauce, and simmer undisturbed until the chicken is fully cook and the sauce has thickened, about 20-30 minutes.
Serve chicken and sauce over prepared cauliflower rice, and top with sprigs of cilantro.