Steps

1. Peel the skin of 2 potatoes, remove any eyes, and cut into 2cm chunks.
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2. Soak the cut potatoes in water for 5 minutes to remove bitterness.
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3. Grate 1/8 onion and place in a bowl.
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4. Add 1 tsp vinegar and 1 tsp sugar to the onion, mix well to remove spiciness.
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5. Drain the potatoes and place in a pot.
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6. Add 400ml water and 1 tsp chicken stock granules to the pot and bring to a boil over medium heat. [This is the trick!] Boiling from cold water increases sweetness and allows the umami of the chicken stock to soak into the potatoes.
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7. Once boiling, reduce to medium-low heat and simmer for about 8 minutes until the potatoes are tender. They are ready when a bamboo skewer slides through easily.
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8. Drain the boiled potatoes in a colander.
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9. Transfer to a bowl while hot and mash. Adjust the mashing consistency to your preference.
   🕒 05:00
10. Add the prepared onion mixture (vinegar and sugar) to the mashed potatoes and mix well. [This is the trick!] Adding the onion while the potatoes are still warm helps to thoroughly remove the onion's spiciness.
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11. Cover with paper to prevent the surface from drying out and let cool. [This is the trick!] Adding mayonnaise when the potatoes are hot can cause separation, so be sure to let them cool completely.
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12. Fill a pot with water and bring to a boil.
    🕒 06:06
13. Once boiling, add 1 tsp salt, gently place 1 M-sized egg, and boil for 8 minutes. [This is the trick!] Salt helps prevent the egg white from leaking out if the shell cracks.
    🕒 06:15
14. Thinly slice 1/2 cucumber.
    🕒 06:44
15. Place the sliced cucumber in a bowl, salt it with 1/3 tsp salt, and let it sit for 5 minutes.
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16. Thoroughly drain the water (or oil) from 1 can of tuna (canned in water or oil).
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17. Squeeze out the moisture from the cucumber after letting it sit for 5 minutes.
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18. Immediately cool the boiled egg in ice water for about 10 minutes and peel. [This is the trick!] Cooling it immediately makes the shell easier to peel.
    🕒 07:47
19. In the bowl with the cooled potatoes, add the hard-boiled egg, roughly mashed with a fork.
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20. Add the tuna and cucumber.
    🕒 09:02
21. Add 2 tbsp mayonnaise, a pinch of garlic powder, and salt and pepper to taste, then mix everything well.
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22. Taste and adjust seasoning as needed.
    🕒 09:24