I think we usually put an H on the end of tempe in the US, i.e. tempeh.
It's a fermented soy protein, like tofu, but with a somewhat different flavor and a very, very different texture. You can find it in a lot of US supermarkets, but it takes some looking.
They say tempe is one of the healthiest kind of food there is, and it helps against a lot of things (aging among other things)
It's nutritionally similar to other soy products, so I'd ask to see the research before expecting some sort of magical superfood benefits.
Actually it isn't nutrionally similar to tofu or soy milk. The whole bean is used, so it contains more protein and vitamins
I'm actually glad I looked it up. From Wikipedia:
"Like tofu, tempeh is made from soybeans, but it is a whole soybean product with different nutritional characteristics and textural qualities. Tempeh's fermentation process and its retention of the whole bean give it a higher content of protein, dietary fiber, and vitamins."