Homemade mashed potatoes with butter.
The Key Ingredients That Make Japan-Style Mashed Potatoes Different
Japanese mashed potatoes typically don’t use American recipe staples, such as sour cream, butter, cream cheese, or milk. Instead, you'll likely taste rice vinegar and Kewpie mayo.
Japanese rice vinegar is made from fermented rice for a slightly sweet flavor, and Kewpie mayo is tangier and contains more umami flavor than most Western brands.
While American recipes can be a little more heavy and one-note, Japanese-style mashed potatoes are lighter and tangier, with a nice balance of tart and rich flavors.
You may taste some sweetness when you take a bite of the mash, thanks to the rice vinegar. It’s still thick and creamy from the Kewpie, which uses only egg yolks in its recipe.