Begin by peeling and cutting 2–3 medium Yukon Gold or Russet potatoes into evenly sized chunks. Place them in a large pot of salted water and bring it to a boil over medium-high heat. Cook for about 15–20 minutes, or until the potatoes are fork-tender. Drain the potatoes, then transfer them to a mixing bowl and mash until smooth, allowing them to cool slightly.

In a separate bowl, combine ½ cup of mayonnaise, 1 tablespoon of sugar, 1 tablespoon of rice vinegar, and 1 teaspoon of mustard (if using). Whisk the mixture until it is creamy and smooth, ensuring all ingredients are well blended. Taste and adjust sweetness or tanginess as desired to balance the flavors of your Korean Potato Salad.

Gently fold the cooled, mashed potatoes into the prepared dressing until they are fully coated. Then, add in 2 diced boiled eggs, ½ cup of finely chopped vegetables such as carrots and cucumbers, and any optional ingredients like chopped apples. Mix everything until well combined, ensuring that each bite of the Gamja Salad has a delightful blend of flavors and textures.

Cover the mixing bowl with plastic wrap or transfer the Korean Potato Salad into an airtight container. Refrigerate for at least 1 hour before serving to allow the flavors to meld beautifully.

Before serving, give the salad a gentle stir to ensure all the components are mixed well. Garnish with additional chopped vegetables or fresh herbs like parsley or chives for a pop of color and extra flavor.