Heat 1 tablespoon of ghee or vegetable oil in a saucepan over medium heat. Add sweet paprika, kosher salt, garam masala blend, coriander powder, ground cumin, turmeric powder, and cayenne pepper. Stir until the mixture becomes fragrant, about 1-2 minutes. Remove from the heat and let cool. In a large bowl, combine the cooled spices, yogurt, lemon juice, minced garlic, and grated fresh ginger. Stir well to create a uniform marinade.
Add the boneless, skinless chicken thighs to the bowl with the marinade. Toss to coat the chicken thoroughly with the marinade mixture. Cover the bowl or transfer to a lidded glass container and refrigerate for at least 30 minutes, or up to 6 hours, allowing the flavors to infuse the chicken.
Preheat the air fryer to 200°C/400°F. Add 1 tablespoon vegetable oil or ghee, chopped onion or shallots, grated fresh ginger, and minced garlic to an air fryer cake barrel or a similar oven-safe dish. Cook for 2-3 minutes until softened. Add tikka curry powder, garam masala, ground fenugreek, brown sugar, salt, crushed or whole tomatoes, and water or passata. Stir to combine and cook in the air fryer for 15-20 minutes, stirring halfway through. Use an immersion blender to blend the sauce until mostly smooth. I like to leave a little texture for a more rustic sauce.
Preheat the air fryer again to 200°C/400°F (or higher if your air fryer allows) for 5 minutes. Lightly mist the basket with oil. Remove the marinated chicken from the fridge and place it into the air fryer basket, discarding any excess marinade. Cook the chicken for 20 minutes, flipping over halfway through until the chicken is juicy and the edges are nicely charred.
Slice the cooked chicken into chunks. Stir the chunks into the blended curry sauce base in the air fryer cake barrel. Pour in the heavy cream or evaporated milk and stir well. Heat everything together in the air fryer for another 5 minutes until the chicken is warmed through and the sauce is creamy and rich. For a touch more richness, I like to use heavy cream instead of evaporated milk here.
Serve the finished chicken curry garnished with fresh coriander leaves. Enjoy with pilau rice and naan bread for an authentic meal! Simply and seriously DELICIOUS!