Mix the yogurt, lemon juice, and spices. Add the chicken and coat well. Let marinate for at least 15 minutes.
In a large pan, melt 2 tablespoons of butter and brown the chicken for 2 to 3 minutes on each side. Set aside.
In the same pan, add 2 tablespoons of butter and cook the onion and cinnamon stick for 5 minutes.
Add the garlic, ginger and paprika. Cook for 1 minute.
Add the crushed tomatoes and let simmer for 10 to 15 minutes until thickened.
Put the sauce in a mixer and blend it until smooth.
Return the chicken to the sauce and let simmer for 8 to 10 minutes.
Add the cream, remaining butter, salt, and pepper.
Add the fenugreek. Let simmer for 5 minutes.
Serve with basmati rice and naan.