Wash, peel and cut 300 g potato(s) into equal thirds or quarters (depending on the size). Place them in a pot and fill with cold water until fully submerged. Add ½ tsp salt and bring to the boil over a high heat and then lower medium. Cook for 12-15 minutes.
While the potatoes are boiling, prepare the other ingredients. Peel and cut 50 g carrot(s) into slices, then cut each circle slice into quarters. Thinly slice 30 g Japanese or Persian cucumber(s).
Place the cucumber into a bowl of cold water with a pinch of salt. Set aside for later.
Heat a frying pan on a medium-high setting and once hot, add ½ tsp cooking oil. Add 40 g bacon, fry until crispy and then remove the pan from the heat.
Once the potatoes have been simmering for about 12-15 minutes, add the carrots and simmer for another 5 minutes.When the potatoes are soft (easy to pierce with a fork), remove the pot from the heat and drain. The carrots should be slightly softened but not mushy. Separate the carrots and potatoes, and mash the potatoes in a large mixing bowl while they're still hot.
Once the mashed potato is smooth, add the bacon and carrot, then mix well.
Drain the cucumber and add them to the mashed potato, mix again.
Add Japanese mayonnaise, black pepper, sugar and sesame oil, and mix until well incorporated.
Leave to cool to room temperature and then cover and refrigerate for at least 30 minutes before serving.
Sprinkle with dried parsley (optional) and enjoy!