Add some salt (not listed in the ingredients) to plenty of boiling water and blanch the spinach quickly to retain the colour. Rinse and squeeze lightly to remove the excess water. Cut into bite sizes.
Sprinkle lightly with salt and gently squeeze out the water. I use salt to do this to retain its nice colour, but it's the same concept as using soy sauce to fix the colour.
Handling the spinach carefully makes it juicy and tender. Season with a small amount of soy sauce and sesame oil.
If garlic-flavoured sesame oil is not available, substitute with a mixture of 2/3 tablespoon of sesame oil and 1/4 teaspoon of salt. The amount of the other ingredients will remain the same.
Add umami seasoning (dashida or Chinese chicken stock granules are also OK), pepper and salt (if necessary), and mix well. Sprinkle with toasted sesame seeds to finish!
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The spinach namul is a staple for bibimbap. When spinach is in season, I make this often. If you keep a stock of garlic-flavoured sesame oil (Recipe ID: 2312035) in your fridge, you can make seasonal vegetable namul anytime.
It is important not to squeeze the spinach too hard! You will have juicy and tender spinach. Soy sauce darkens the colour, so just add a tiny bit to season with. Since the size of 1 bunch of spinach depends on the season, adjust the seasonings to taste.