Canary Islander Rosana Arbelo, singing her own composition, En Navidad. Rosana, who goes by her first name only, is very popular in her native Spain, as well as in Latin America.
World famous Cuban-American singer Gloria Estefan performing a Christmas song called Mas Alla (Beyond).
Here's an oldie but goodie: Spain's Jose Luis Perales singing a song he wrote in the 70s, Cancion Para La Navidad. This is a video of a live TV performance of the song broadcast in 1985.
Speaking of oldies but goodies, here's Puerto Rican singer / songwriter Jose Feliciano singing his composition, Feliz Navidad, probably the most famous Spanish Christmas song. In fact, its one of the 25 all-time most-played Christmas songs in the world.
Merry Christmas / Feliz Navidad, Carloz