In a small saucepan, combine brown sugar, water, butter, and salt. Cook over medium heat, stirring constantly, until the sugar dissolves and the mixture thickens into a caramel sauce. Remove from heat and set aside.
Place a banana half on a lumpia wrapper.
Fold the bottom edge of the wrapper over the banana. Fold in the sides, then roll it up tightly. Moisten the edge with water to seal.
Heat oil in a frying pan or deep fryer to 350 degrees Fahrenheit (175 degrees Celsius).
Carefully place the lumpia in the hot oil and fry for 2-3 minutes, or until golden brown and crispy.
Remove from the oil and drain on paper towels.
Drizzle with caramel sauce and serve warm.
Notes
Use ripe but firm bananas for the best texture.
If your lumpia wrappers are dry, brush the edges with water to help them seal.
Make sure the oil is hot enough before frying to ensure crispy lumpia.