Remove the ice cream from the freezer and let it soften. Grease and line the base of a 20 cm (8 inch) loose-based fluted flan tin.
Melt the olive oil spread in a pan. Combine the melted olive oil spread with the biscuit crumbs and press the mixture into the base of the prepared tin.
Toss the bananas in the lemon juice and scatter over the biscuit base.
Spread the ice cream on top of the bananas, using a palette knife to evenly cover them.
Scatter the chocolate bar slices over the top of the ice cream. Freeze for at least 1 hour before serving.