Heat 2 tablespoons of coconut oil in a skillet over medium heat. Add the finely diced yellow onion and sauté for about 5 minutes until softened and translucent. Stir in the freshly minced ginger and garlic, cooking for an additional 30 seconds until aromatic. Then mix in curry powder, garam masala, chili powder, kosher salt, and tomato paste, allowing the spices to bloom.

Carefully transfer the sautéed aromatic mixture into the bottom of your slow cooker. Spread it evenly across the bottom.

Place the boneless, skinless chicken breasts on top of the aromatic mixture. If using, scatter the cauliflower florets over the chicken. Next, pour in the tomato sauce, gently stirring to combine while keeping the chicken on the bottom. Scatter unsalted butter pieces on top.

Cover the slow cooker and cook on high for 1.5 to 2.5 hours or low for 4 to 6 hours. Ensure chicken reaches an internal temperature of 165°F.

Once cooking time is complete, check the cauliflower for doneness. If still firm, cover and cook on high for an additional 30 minutes to 1 hour.

Remove the chicken from the slow cooker, slice into bite-sized pieces, and return to the pot. Stir in the half-and-half or coconut milk and Greek yogurt until well combined.