Slice the bananas in half lengthways in their skins. In a bowl, mix the lemon, sugar and butter together and brush on the cut side of each of the bananas.
Heat the barbecue until very hot. Grill the bananas, cut-side down, for about 4 minutes or until browned with deep grill marks.
Heat the dulce de leche sauce in a saucepan over a gentle heat, then pour into a serving jug. Remove the bananas from their skins, then drizzle the dulce de leche sauce over the fruit. Serve the caramel bananas with a scoop or two of vanilla ice cream.
For more deliciously indulgent ideas, see Dessert recipes.