Chicken Tikka Masala

Name: Chicken Tikka Masala
Ingredients: 1/2 cup sour cream; 1 tablespoon mild or hot curry powder; 1 1/2 teaspoons paprika; Kosher salt; 1 pound boneless skinless chicken thighs, excess fat trimmed; 3 cloves garlic, roughly chopped; One 1/2-inch piece ginger, roughly chopped; 1 small onion, roughly chopped; 1 tablespoon vegetable oil; 2 teaspoons garam masala; One 28-ounce can no-salt-added tomato puree; 2 cups cauliflower florets; 2 tablespoons unsalted butter; 3 tablespoons chopped fresh cilantro, plus more for garnish; 6 cups cooked brown rice, for serving; Lemon wedges, for serving