1. Combine all the ingredients for the filling in a bowl and mix well. Heat 1–2 tablespoons of oil in a large frying pan over a medium-high heat, add the lamb filling and cook, stirring, until it is cooked through. Taste and adjust the seasoning as needed. Transfer to a bowl and allow to cool.
2. Line a tray with baking paper. Place one spring roll wrapper on a chopping board, storing any unused wrappers under a clean tea towel so they do not dry out. Spread 1–2 tablespoons of the filling over one half of the wrapper, leaving a 1 cm border. Cut a thick slice of the banana with the skin on and rub the banana flesh over the edges of the wrapper to help seal the skin together (if you prefer, you can brush with beaten egg). Fold the other half of the wrapper over the filling and press all the edges down. Place on the tray. Repeat until all the filling has been used up.
3. Fill a deep saucepan one-third full with sunflower oil and heat to 160°C. (If you do not have a kitchen thermometer, check the oil is at temperature by adding a cube of bread; it should turn golden in 25–30 seconds.) Fry the martabak in batches for 2–3 minutes until golden. Transfer to a tray lined with paper towels to absorb any excess oil.
4. Cut the martabak in half so the filling can be seen, then serve.
Note
• If you want to make the recipe vegan, replace the lamb with 225 g potato and 225 g butternut squash. Peel them both, removing the seeds of the butternut squash, and cut into 5 mm cubes. Preheat the oven to 220°C fan. Place on a flat baking tray, drizzle all over with oil, and season with salt. Place two garlic bulb halves on the tray to add flavour. Bake in the oven for 15 minutes or until cooked through. Meanwhile, cook the remaining filling ingredients with 1 tablespoon of oil in a frying pan over a medium heat until softened, then stir through the roasted squash and potato.
Recipe and image from Coconut & Sambal by Lara Lee, Published by Bloomsbury (RRP $39.99)