I’ve only done it once, but I was a little surprised to find Sriracha Sauce works alright with UU Huel. It wasn’t amazing or anything but I’d do it again. It is nice to have a simple variant that is not a fruit or other sweet flavor.
I was inspired by the successful reports of mixing with a spicy V8 blend because I was jealous and wanted spicy Huel too.
I would caution about adding too much as I think the flavor could become too vinegary and risk ending up with a combination like dill pickle juice.