01 - Combine yogurt, lemon juice, ginger-garlic paste, cumin, coriander, chili powder, garam masala, and salt in a bowl. Add chicken pieces and coat thoroughly. Cover and refrigerate for at least 30 minutes or up to 2 hours.
02 - Melt 2 tbsp butter in a large skillet over medium heat. Sauté onions until golden, about 5 minutes. Add marinated chicken, reserving any leftover marinade, and cook until lightly browned, approximately 6-7 minutes.
03 - Add crushed tomatoes, reserved marinade, and sugar to the skillet. Simmer for 10 minutes. Stir in heavy cream and remaining 1 tbsp butter. Cook for 5-7 more minutes until sauce thickens and chicken is cooked through. Adjust salt to taste and garnish with fresh cilantro.
04 - Combine grated zucchini, carrot, onion, peas, corn, eggs, all-purpose flour, chickpea flour, turmeric, cumin, chili powder, salt, pepper, and baking powder in a large bowl. Mix until a thick batter forms.
05 - Heat oil in a large skillet over medium heat. Drop heaping tablespoons of batter into the pan, flattening slightly. Fry for 2-3 minutes per side until golden and crispy. Drain on paper towels.
06 - Serve butter chicken hot alongside freshly made vegetable fritters. Pair with steamed rice or naan bread for a complete meal.