Nutritional yeast, aka flake yeast.
Intense flavor, goes with damm near anything parmesan goes with, and things it doesn't. It's fairly cheap, lasts ages when stored decently, and it packs a nutritional punch.
People like to talk about how umami's spread as a specific flavor into awareness in the west was a massive shift. But a lot of people got locked into the soy and fish sauce focus that was the first thing that western tastes became familiar with as umami. Even when folks are aware of other things, they still tend to think in terms of sauces and complex recipes for pastes and fermented products. But good old yeast is right there, cranking out a deep and rich flavor.
So it gets slept on pretty hard. It doesn't help that it isn't marketed well. A lot of people that have heard of it think it's more along the lines of a vitamin you take on its own, or lump it in with woowoo nutrition in places where it's called nutritional yeast.
One of my favourite things that really focus on it as a major flavor component is roasted cauliflower. You mix it with the spice blend, and toss it in a bowl, and it opens up with that rich, heady scent that yeast has. I don't measure for it, it's just dumping a bit of garlic and onion powders, salt & pepper, then some paprika. Then maybe two to three tablespoons of the yeast. It's mouth watering, just the smell. Fuck, my mouth is watering thinking of it.
You get that amazing caramelized flavor from the roasting, that delicate floral note that some cauliflower has, the slightly sulfuric tang too. Then the spices lift those, and the yeast ties it all together and becomes greater than the sum of its parts.