In a mixing bowl, combine the minced ginger, minced garlic, lemon juice, chopped chicken thighs, and tandoori curry paste; mix until the chicken is evenly coated.
Heat 1 tablespoon butter in a non-stick skillet over medium heat.
Add the marinated chicken and cook 3–4 minutes, stirring, until the exterior is no longer pink; transfer the chicken to a plate.
In the same pan, add 2 tablespoons ghee and the sliced onion; cook until the onion is softened, about 3–4 minutes.
Add the garam masala, cumin, and smoked paprika to the onions and cook 30–60 seconds until fragrant.
Return the chicken to the pan, then add the crushed canned tomatoes and chicken broth and bring the mixture to a simmer.
Simmer until the sauce reduces slightly and begins to thicken, about 5–8 minutes.
Stir in the heavy cream and simmer gently for 10–12 minutes, stirring occasionally, until the sauce is thick and the chicken is cooked through.
