Yellow Sauce Sometimes Served on Hot Dogs
Puzzle 17 of Fast Food Piece of Cake Pack
Question is: Yellow Sauce Sometimes Served on Hot Dogs
and the answer is: MUSTARD
Word Meaning:
MUSTARD — A plant of certain species of the genus Brassica, or of related genera (especially Sinapis alba, in the family Brassicaceae, with yellow flowers, and linear seed pods).
Definitions from Wiktionary.