In what region do you live? When during the year was the photo taken? How big was the fungus? What type of tree was this on? Tree alive or dead? I have a few types I think it might be, so whatever info you have would be great.

As best as I can figure out, this is a Chicken Mushroom (Laetiporus sulphureus), also known as the Sulfur Shelf. Here's a description:

Single to overlapping clusters of fleshy, smooth, orange-red to orange-yellow caps with sulfur-yellow spores.
Cap: 2-12" wide; usually overlapping, flat, semicircular to fan-shaped; salmon to sulfur-yellow or bright orange, weathering to white; smooth. Flesh 0.4-2 cm thick, white, light yellow, or pale salmon.
Edibility: Choice
Season: May-November
Habitat: On stumps, trunks, and logs of deciduous and coniferous trees and buried roots.
Range: E. Canada to Florida; Midwest; Pacific NW to California.
Comments: Also called the "Sulfur Shelf" and Polyporus sulphureus. This popular mushroom can grow in large overlapping clusters of 5 to 50 or more, with shelves weighing up to a pound each, or in rosettes 10-30" wide. A choice edible, it tastes like chicken. It becomes somewhat indigestible as it ages and, in some, causes an allergic reaction, such as swollen lips. Specimens from a few tree hosts, such as eucalyptus, can cause digestive upset. A variety, semialbinus, has a salmon-colored cap and white spores.

*****WARNING*****

This is my best guess. DO NOT TAKE THIS AS A CONFIRMATION. DO NOT EAT THIS UNTIL YOU HAVE AN EXPERT LOOK IT OVER. THIS IS ALL BASED OFF OF A PHOTO, WHICH IS NOTORIOUS FOR BEING WRONG.

That said, I think it's a chicken mushroom, but you should have someone who can look at it personally (if and when it returns), to verify. If it is, then cut that summbich off, fry 'er up, and dig in!

That Sulfur Shelf suggested sounds just about right.

I've just started to become familiar with a few of many, the past several years.

Slowly filling in the captions ...

Here is a link that might be useful: Oregon Mushroom Photos