Line the base and sides of the tin with non-stick baking parchment and preheat the oven to 180?/Fan 160?.

Chop the rhubarb stems into smallish chunks and the half each chocolate button.

Put the caster sugar, golden syrup and spread into a large pan.

Heat, stirring occasionally, until the sugar dissolves and butter melts.

Tip the oats into the pan and mix well. Finally, stir in the rhubarb chunks and chocolate.

Tip the mixture into the prepared tin and press down firmly (a potato masher is useful here).

Bake in the preheated oven for about 25 minutes until the outside edges are golden brown. Leave to cool before cutting into squares.

Best kept in the fridge