Prepare all ingredients as instructed above.
Marinate the chicken: In a bowl, mix yogurt, lemon juice, ginger paste, garlic paste, garam masala, turmeric, chili powder, and salt. Add chicken pieces and coat well. Cover and marinate for at least 30 minutes.
Cook the rice: Cook the brown rice according to package instructions. Once tender, fluff with a fork and season with salt and black pepper. Cover and keep warm.
Prepare palak paneer: Bring a pot of salted water to a boil. Add spinach and blanch for 2–3 minutes until wilted. Transfer immediately to ice-cold water to retain the green color.
Make the spinach purée: In a blender, combine blanched spinach, tomato, garlic, ginger, and green chili. Purée until smooth. Set aside.
Cook the spinach sauce: Heat olive oil in a pan over medium heat. Add chopped onion and sauté until it begins to change color. Stir in the spinach purée and water. Cover and cook for 10 minutes, stirring occasionally. Add garam masala, turmeric, chili powder, and salt. Cook for 1 minute. Stir in the cream. Add paneer cubes and simmer for 3–4 minutes. Turn off heat and add lemon juice. Set aside.
Make the cucumber raita: In a medium bowl, whisk the yogurt until smooth and creamy. Stir in the cucumber, cilantro, lemon juice, cumin, salt, and pepper. Cover and refrigerate for at least 5 minutes to allow flavors to meld. Stir once before serving.
Make butter chicken: In a separate pan, melt butter over medium heat. Add chopped onion and cook until translucent. Add garlic, ginger, cumin, and coriander. Cook for 1 minute until fragrant. Add crushed tomatoes and cook until oil separates from the mixture.
Add the marinated chicken: Stir in the marinated chicken along with its marinade. Saute until the chicken lightly browned. Stir in cream and fenugreek leaves (if using). Simmer until the chicken reaches an internal temperature of 160F / 71C and the sauce thickens. Adjust seasoning if needed.
Warm naan bread in a nonstick pan over medium heat until both sides are soft and lightly browned.
Combine the water with lemon.
Serve butter chicken with rice, naan, palak paneer, cucumber raita, and lemon water.