2.Cut the potatoes into bite-size pieces, add a little water and microwave for 5–8 minutes. Meanwhile dice the cucumber and carrot. I was eating it right away, so I didn't salt the cucumber!
3.Mash the potatoes and mix with the carrot, cucumber, mayonnaise, wholegrain mustard, salt, pepper, lemon juice and honey.
4.Spread basil pesto on one side of the bread, add arugula, cheddar, jambon and the potato salad, and close — done!