Prepare the Potatoes:

1. Peel and chop the Russet potatoes into chunks.
2. Boil the potatoes in a pot of salted water for about 10-15 minutes or until tender.
3. Drain the potatoes and mash them in a large bowl until smooth.

Make the Potato Mochi Dough:

1. To the mashed potatoes, add the potato starch, 3 tablespoons of water, and Himalayan salt. Mix until a smooth dough forms.
2. If the dough is too dry, add another tablespoon of water as needed.
3. If desired, stir in the salted butter for extra flavor and richness (optional).

Shape the Mochi:

1. Divide the potato dough into small portions and shape them into flat, round discs, about 2 inches in diameter. Set aside on a plate.

Fry the Mochi:

1. Heat enough oil in a frying pan over medium-high heat to cover the bottom of the pan.
2. Once the oil is hot, add the potato mochi discs in batches, frying them for 2-3 minutes on each side or until they turn golden brown and crispy.
3. Remove the mochi from the pan and drain on paper towels to remove excess oil.

Make the Sauce:

1. In a small saucepan, combine the tamari or soy sauce, blended raw cane sugar, and rice vinegar (or mirin).
2. Warm the mixture over medium heat, stirring until the sugar has completely dissolved.
3. Allow it to simmer for 1 to 2 minutes to achieve a slightly thicker consistency, then take it off the heat.

Serve:

1. Serve the crispy fried potato mochi warm with a side of the sweet and savory sauce for dipping. Enjoy!