Put refined flour in a large mixing bowl, add cornstarch, baking soda, sugar, vanilla essence, pumpkin puree and sufficient milk and whisk well to make a thick batter. Rest the batter for a few minutes.
Heat sufficient oil in a deep frying pan.
Peel and cut bananas into thick diagonal slices. Dip each slice well in the batter, shake off excess batter and slide into hot oil and deep fry till golden. Drain on absorbent paper.
Arrange them on a serving plate, sprinkle little powdered sugar and drizzle chocolate sauce and serve hot.