Mix flour, sugar, salt, and yeast in a large bowl. Add warm water and oil, then knead into a smooth dough. Cover and let rise for 1 hour until doubled in size.
Heat 2 tablespoons oil in a pan and fry fennel seeds until fragrant. Add chopped onion and sauté until translucent.
Add carrots, potatoes, and green beans to the pan. Cook for 5-7 minutes until vegetables begin to soften.
Stir in chopped tomatoes, salt, turmeric, chili powder, cumin powder, and garam masala. Mix well.
Add tomato ketchup, ground cashew paste, and water. Simmer until the mixture thickens and vegetables are fully cooked. Let cool completely.
Divide the risen dough into 8 equal portions. Roll each piece flat, place a spoonful of cooled curry filling in the center, and seal edges to form balls.
Dust each filled ball lightly with cornflour, then roll in panko breadcrumbs to coat completely.
Heat oil to 350°F (175°C) for deep frying. Carefully fry the coated balls until golden brown and crispy, about 3-4 minutes per side.
Remove and drain on paper towels. Serve warm.