Red Onions vs. Yellow Onions – Is There a Difference?

Red onions have a deep purple skin and reddish flesh, but do they really taste different than yellow onions? They are quite like yellow onions in flavor when cooked, and slightly milder when served raw. Their deep color is what makes these attractive added to salads, and other foods for presentation. But once these onions are cooked, they taste very nearly the same as the yellow onion and can be used in recipes to substitute yellow onions (or vice-versa … use yellow onions to substitute red onions.