01 - Preheat oven to 400°F.
02 - Slice zucchinis in half lengthwise. Using a spoon, scoop out the centers leaving approximately 1/4-inch thick shells. Reserve about 1/2 cup of the scooped flesh and finely chop it.
03 - Brush the cut sides of zucchini boats with olive oil and season generously with salt and pepper. Arrange cut-side up on a rimmed baking sheet.
04 - In a large skillet over medium heat, melt butter. Add onions and cook until softened and translucent, about 3 minutes. Add garlic, ginger, and reserved chopped zucchini flesh. Cook for an additional 2 minutes until fragrant.
05 - Add diced chicken to the skillet. Cook, stirring occasionally, until chicken is browned on all sides and cooked through, approximately 5 to 6 minutes.
06 - Stir in tomato purée, garam masala, cumin, coriander, chili powder, turmeric, salt, and pepper. Simmer for 8 minutes, stirring occasionally to prevent sticking.
07 - Reduce heat to low. Add heavy cream and Greek yogurt, stirring constantly until fully incorporated and sauce is creamy and smooth. Simmer for an additional 2 to 3 minutes. Taste and adjust seasoning as needed.
08 - Spoon the butter chicken mixture evenly into each prepared zucchini boat, mounding slightly. Top each with shredded mozzarella cheese if desired.
09 - Bake in preheated oven for 18 to 20 minutes, or until zucchini is tender when pierced with a fork and cheese is melted and golden brown.
10 - Remove from oven. Sprinkle with fresh cilantro and mint. Serve immediately while hot.