Line a small baking tray with non-stick baking paper. Be sure to check that the tray will fit inside your fridge before you line it.
Wash and dry the grapes, making sure that they are as dry as possible. Break the dark chocolate into pieces and place in a small microwave safe bowl.
Melt the chocolate in the microwave in 30 second bursts, stirring between each one to ensure it melts evenly. Be careful not to overheat or burn the chocolate, heat only until just melted and smooth.
Dip the grapes into the chocolate to cover the bottom third of each grape, then place on the lined baking tray. Repeat until you have made as many grape ‘haycorns’ as you want, then place the tray of grapes into the fridge for 15-20 minutes to set.
Line a lunch box with large lettuce leaves, and half fill with baby carrots. Fill the other side of the box with the grape haycorns, once set.