Logging verbose output of cp to a file?

Sorry for the novice question, I cannot seem to figure out how to log the verbose output of cp to a file.

I am doing cp -Rv /source/folder /destination/folder | tee output.log (this is not working)
Also tried cp -Rv /source/folder /destination/folder >> output.log (also not writing to file).

I want the verbose output to be displayed both in the terminal window as the copy happens and I also want that verbose output written to a file. What am I missing?