South Indian Vegetable Curry

Name: South Indian Vegetable Curry
Ingredients: 1 large onion, cut into 1-inch chunks (about 2 cups); 3 large garlic cloves, peeled; 1 2-inch-long 1-inch-diameter piece peeled fresh ginger (about 2 ounces); 3 tablespoons sunflower oil; 1 tablespoon garam masala; 2 teaspoons ground cumin; ½ serrano chile, seeded, chopped; 2 tablespoons tomato paste; 3 cups vegetable broth; 2 teaspoons (packed) golden brown sugar; 2 Makrut lime leaves; 2 whole green cardamom pods; 1 pound red-skinned sweet potatoes (yams), peeled, cut into 1-inch cubes; 12 ounces russet potatoes, peeled, cut into 1-inch cubes; 1¼ cups finely grated peeled fresh coconut (about 4 ounces; grated in processor); 2 large carrots, peeled, cut into 1/2-inch rounds; 2 tomatoes, cored, chopped; 1 teaspoon salt; ¼ teaspoon freshly ground black pepper; 4 ounces baby spinach leaves (optional); 2 tablespoons chopped fresh cilantro