Preheat the oven to 180ºC/gas mark 4. Put the rhubarb in a roasting tray. Pour the orange juice, vanilla extract and honey into a small jug and whisk together, then pour over the rhubarb. Bake for 10 minutes, until the rhubarb is tender. Leave to cool.
Mix together the yogurt, ginger and icing sugar. Crush 3 of the shortbread biscuits.
When the rhubarb has cooled, spoon into 6 serving glasses, layering with the yogurt mixture. Sprinkle the crushed shortbread on top and garnish with mint leaves. Serve with a whole shortbread on the side.