Slice potatoes to resemble hasselback accordion shape. You may use chopsticks to help guide you so that you don’t slice through the entire potato. Place two chopsticks flat on a chopping board and the potato in between (as if the potato were skiing with chopsticks). Hold the potato with one hand and begin slicing down. Each slice should be thin, around ⅛ apart, or smaller. Repeat and do this to all potatoes. The chopsticks are optional. If you feel you can do this better without any tools, you may use your own judgement to slice.
Brush with miso butter and roast.
Preheat oven to 395°(201°C). Line the potatoes on a baking sheet and set aside as you prepare miso butter. In a small saucepan, add miso and butter over low-medium heat. Allow the miso and butter to melt and stir to combine well. This shouldn’t take long, about 5 minutes or less.
When the miso butter mixture is ready, use a pastry brush to brush the miso butter onto each potato. Remember to get all the crevices of the potatoes, so use a dabbing motion to get the miso butter in between the slices. Roast potatoes for 20-25 minutes, or until golden brown and crispy.
Make nori seasoning.
While the potatoes are roasting, prep the nori seasoning. Add nori sheet in a food processor and pulse until the nori is broken down into small bits. It should resemble small flakes. If you want it even finer, pulse longer to get to desired texture. Once the nori is at the desired fineness, add sesame seed, togarashi and salt. Stir well to combine.
When the potatoes are done roasting, toss them in the nori seasoning while hot.
Mix wasabi and crème fraîche.
To make wasabi crème fraîche, mix wasabi, and crème fraîche in a small bowl using a spoon. Taste as you go in order to adjust based on spiciness. It’s better to add less wasabi at the beginning and gradually add more. Salt to taste.
Mix Sriracha and mayonnaise.
To make Sriracha mayo, mix Sriracha, mayonnaise and rice wine vinegar in a small bowl using a spoon. Taste as you go in order to adjust based on spiciness and tanginess. It’s better to add less Sriracha at the beginning and gradually add more. Salt to taste.
Plate and serve.
Spread the wasabi crème fraîche on a serving dish using a large spoon. Add the potatoes over, and top with Sriracha mayo. Alternatively, you can serve the wasabi crème fraîche and Sriracha mayo in small bowls as dipping sauces. Garnish with sesame seeds. Congrats! You just made Japanese inspired Hasselback Potatoes.