Quinoa is a great source of vegan protein. These tasty seeds are a complete source of protein, very rare in the plant world (usually, vegetarians have to combine beans and grains to get the full range of amino acids). When quinoa first became popular in the United States, many of the kosher certification organizations suspected that it might be kitniyos, a class of foods that are not forbidden on Passover by the Torah but are forbidden to Ashkenazim (Eastern European Jews) by longstanding custom. In the last few years, however, major kosher certification organizations like OU, Star-K and CRC have accepted quinoa as kosher for Passover, by Orthodox standards.
You will be happy to know that Ancient Harvest brand quinoa, the most widespread brand and my personal favorite, is KOSHER FOR PASSOVER WITHOUT SPECIAL CERTIFICATION! The Star K organization, which certifies Ancient Harvest year-round, has said in their 2016 Passover Directory that all three of Ancient Harvest's quinoa seed products are kosher for Passover, without the need for a "P" next to the Star-K logo.
This ruling applies ONLY to the seed products, not to their many other quinoa based products, like pastas and cereals.
Coming soon... four different recipes for kosher-for-Passover pizza!