When I cooked the pechay guisado last week, I reserved the dark green leaves of the pechay for a vegetarian soup. In an attempt to tweak the depth of flavor, instead of using salt, I switched to a mixture of soy sauce and salt to season the broth. It was a new technique for me because I’ve always associated soy sauce with stir fries and stews, never for soups. If soy sauce had to go into a soup at all, it would be as a condiment served on the side.
And just what prompted me to season the broth partly with soy sauce? Well, ramen is sometimes served with broth flavored with ponzu sauce which is a mixture of soy sauce and citrus juice. I’ve always loved ramen with a ponzu based, so, why not soy sauce in a tofu soup?
The revelation was that I kind of blamed myself for not thinking of using soy sauce to season broth long ago. I should have, really. The broth not only acquires a more attractive hue; the dimension of the flavor also changes dramatically. Despite the simplicity and the very few ingredients that went into it, the soup was rich with that mysterious earthy smoky saltiness that only soy sauce can impart. Probably not surprising considering the process of making soy sauce. It takes months to make soy sauce but the best kind takes years to produce to allow the flavors to develop fully. Or so the traditionalists say.
In this recipe, there are options. For non-meat but not exactly vegetarian eaters, broth made with chicken, pork or beef bones makes a wonderful base. For vegans, switch to vegetable broth.
I added fried shallots to the broth during cooking to add even more depth.
If you’re wondering why the seasoning is soy sauce PLUS salt, it’s because seasoning with soy sauce alone would have turned the broth too dark and I really didn’t want that. I was aiming for a golden brown hue which, to my mind, set off the whiteness of the tofu and the bright green color of the pechay leaves perfectly.
Heat the broth. Season with soy sauce and salt.
When the broth simmers, drop in the tofu and fried shallots, if using.
Simmer for about five minutes. Taste the broth and adjust the seasonings as the tofu is like a sponge that soaks up salt.
Drop in the pechay leaves, pushing them into the broth.
Turn off the heat, cover and leave for another five minutes to allow the pechay leaves to cook in the residual heat.