Remove the roots from the spinach and rinse under running water to clean.

Boil water in a pot, add a pinch of salt, and blanch the spinach for 30–40 seconds.

Drain the spinach and rinse it several times in cold water. Squeeze out excess water.

Finely chop the onion and soak it in cold water to remove its sharpness.

Drain the onion and pat dry with a kitchen towel.

Mix the seasoning ingredients (gochujang, soy sauce, plum extract, sesame oil, sesame seeds, minced garlic) in a bowl.

Add the chopped onion to the seasoning mixture and stir well.

Gently mix the spinach with the seasoned onion mixture.