Prepare the chocolate filling: In a small saucepan, melt the butter over low heat. Add the chocolate chips and stir until melted and smooth. Stir in vanilla extract and set aside.

1. Prepare the bananas: Slice the bananas into 1/2 inch thick pieces. Optionally, sprinkle with sugar to sweeten the bananas.
2. Assemble the spring rolls: Lay a spring roll wrapper on a flat surface, with one corner facing you. Place a few slices of banana in the center and drizzle with a small spoonful of melted chocolate.
3. Roll the spring rolls: Fold the bottom corner over the filling, fold in the sides, and roll tightly towards the top corner, sealing with water.
4. Fry the spring rolls: Heat about 1 inch of vegetable oil in a frying pan over medium heat. Fry the spring rolls for 2-3 minutes on each side until golden brown and crispy.
5. Drain and cool: Place fried spring rolls on a paper towel-lined plate to drain excess oil. Let cool slightly before serving.
6. Serve: Dust with powdered sugar if desired. Serve with vanilla ice cream or a drizzle of caramel sauce for added indulgence.