Fill a large saucepan with about 1 inch of water, insert a steamer basket, and bring to a boil over high heat. Lower the heat to medium-high and place the sweet potato in the steamer. Cover and steam for 12 to 15 minutes, until the potato is tender. Set the sweet potato aside until cool enough to handle, then remove and discard the skin.

In a blender or food processor, combine the flesh of the sweet potato, chickpeas, nutritional yeast, miso, turmeric, umami blend, and vinegar and purée until smooth. While blending, slowly add broth until the sauce is easy to pour but still thick.

Use immediately or transfer to an airtight container and store in the refrigerator for up to 5 days. Reheat the sauce in a saucepan with just a little water to thin it out before using.