01 - Preheat oven to 400°F.
02 - Slice zucchinis in half lengthwise. Scoop out centers with a spoon, leaving 1/4-inch thick shells. Reserve inner flesh and chop.
03 - Brush zucchini boats with olive oil and sprinkle with salt and pepper. Place on baking sheet.
04 - In large skillet over medium heat, melt butter. Sauté onions until soft, about 3 minutes. Add garlic, ginger, and reserved chopped zucchini flesh. Cook 2 minutes more.
05 - Add diced chicken to skillet. Cook, stirring, until browned on all sides, about 5-6 minutes.
06 - Stir in tomato purée, garam masala, cumin, coriander, chili powder, turmeric, salt, and pepper. Simmer 8 minutes, stirring occasionally.
07 - Reduce heat to low. Add cream and Greek yogurt, stirring until sauce is creamy and chicken is fully cooked. Simmer 2-3 minutes. Adjust seasoning.
08 - Fill each zucchini boat with butter chicken mixture. Top with mozzarella if using.
09 - Bake in preheated oven 18-20 minutes, until zucchini is tender and cheese is golden.
10 - Remove from oven and top with fresh cilantro and mint. Serve warm.