Knew that immediately - Shades of Grey by Cindy Leuch.

Here's another:
Quote
A single light was burning in Clark Kent's apartment. In the muted glow, in the middle of the living room, Lois Lane was standing gazing at the object she'd just discovered, her jaw slowly dropping.

After a long moment she sat down abruptly on the couch and swallowed hard. "I just can't believe it!" she muttered.
Wendy smile

Just a fly-by! *waves*