This is a very simple way to create a vegetable stock with a rich umami taste. There are two parts to building the flavors in this stock. The first involves steeping the dried shiitake in water maintained between 140°F and 158°F [60°C and 70°C] to allow the ribonuclease enzyme to produce the umami nucleotides. The second part is to apply the caramelization and Maillard reactions to the vegetables and sauté them in the absence of any added water or oil over low heat. This produces brown-colored pigments, and the bittersweet and aroma molecules along with the umami molecules give this vegetable stock its rich meaty profile.