We finished the handle with Emmet's "Good Stuff" rub-on, wipe off gel varnish. Gel varnishes are great finishes because they are easy to work with, bring out a nice satin luster in the wood, and dry in no time, without all the trouble of brush on polyurethane.
Coat the handle in gel varnish and work it into the wood. Wait 20 minutes. Wipe off any excess that remains and let dry for several hours. Repeat the process once or twice more for additional protection since this will be used with a kitchen appliance and will be hand-washed in the sink.
That's it - the portafilter is finished - now go pull some shots!