2 tablespoons dulce de leche or thick caramel sauce
1 teaspoon bicarbonate of soda
1 tablespoon boiling water
Line 2 baking sheets with nonstick baking paper. Place the banana chips in a freezer bag and tap lightly with a rolling pin to break them up, but not crush completely. Tip into a bowl, then add the flour, oats, fudge chunks and sugar and mix until combined.
Place the butter and dulce de leche or caramel sauce in a small saucepan over a low heat and warm until just melted. Put the bicarbonate of soda in a small bowl and stir in the boiling water. Add to the melted butter, then stir into the dry ingredients.
Use lightly floured hands to roll the mixture into about 25 walnut-sized balls, then place on the prepared baking sheets.
Bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 10 minutes, or until golden. Leave to cool on the sheets until firm, then transfer to wire racks to cool completely.