Mix 2 tablespoons of the sour cream, 1/2 teaspoon of the curry powder, 1/2 teaspoon of the paprika and 1/4 teaspoon salt in a medium bowl. Add the chicken thighs and toss to evenly coat. Cover the bowl and marinate for 30 minutes at room temperature.
Meanwhile, pulse the garlic, ginger, onions and 2 tablespoons water in a food processor until smooth. Heat the vegetable oil in a 6-quart Dutch oven or large pot over medium-high heat. Add the onion mixture, the remaining 2 1/2 teaspoons curry powder, the garam masala and the remaining 1 teaspoon paprika. Cook, stirring occasionally, until the mixture starts to stick and brown on the bottom of the pan, about 4 minutes. Add the tomato puree, 1 cup water, the cauliflower and 2 teaspoons salt. Cover partially with a lid and simmer gently until the cauliflower is tender, 25 to 30 minutes.
Meanwhile, preheat the broiler with a rack positioned about 4 inches from the heat source. Line a baking sheet with foil. Arrange the chicken thighs in one layer. Broil 8 to 10 minutes, flipping halfway through. The chicken should be browned and just cooked through (if it chars too much, lower the rack). Cut into large chunks.
Once the cauliflower is cooked, remove from the heat and stir in the chicken, the remaining 6 tablespoons of sour cream, the butter and cilantro. Divide the rice, tikka masala and lemon wedges evenly among six bowls. Garnish with cilantro.
From Food Network Kitchens