Vegetable broth paste can be found among the other types of broth available in certain grocery stores. It can be replaced here with the same quantity of miso paste.
There are several types of tofu available on the market. There can be significant differences between various types of semi-firm tofu, depending on the brand. For best results with this recipe, choose a semi-firm tofu that is soft and smooth (such as semi-firm Sunrise tofu or Mori-Nu tofu), instead of opting for a variety that is dense and compact.