Heat oil in a large, heavy pot over high. Add chicken; cook, turning occasionally, until browned, 5 to 6 minutes. Add onion, garlic and ginger; cook, stirring constantly, 2 minutes. Add tomato paste, turmeric, garam masala and cayenne; cook, stirring constantly, until spices are toasted and fragrant, about 2 minutes. Stir in tomato puree, stock, cream, salt and pepper. Bring to a simmer over medium-high. Reduce heat to medium and simmer, stirring occasionally, until sauce is thickened slightly, about 10 minutes. Stir in cilantro; serve over rice.