Finger Lickin' Fifteen is a bit of departure for Evanovich because the main crime seems to get less attention than the subplot. The headless man is celebrity chef Stanley Chipolte and there's a million dollar reward for solving his murder so Lula and Grandma Mazur decide to enter the cook-off in an attempt to find the killer. Even with the help of Lula's new man, a cross-dressing fireman who bears at least a passing resemblance to Julia Child, they are far from successful. This thread focuses more on the home aspect of Steph's life - the killers are found but the murder takes a back seat to Lula's and Grandma's attempts to make non-burnt, non-toxic barbecue sauce. It does allow Evanovich to channel her inner teenager, with a lot of bodily function humor, most of it from Lula.
The RangeMan plot is a little tighter, and gives Steph a chance to show that she's not merely lucky. Several of RangeMan's security clients have been burgled, and it looks like an inside job. Steph's job is to casually investigate the RangeMan employees while doing background searches for clients. This turns out to be a dead end, but while visiting a recent break-in with Ranger, she figures out how the crime were committed. Using that information, they lay a trap for the robbers and save the security business.
Finger Lickin' Fifteen is well plotted, but the plot is really just a framework against which the insanity of Steph's life is set. So we get multiple Car Deaths, a family dinner (with the cross-dressing fireman and a produce manager named Peter Pecker whom Steph's mom thinks could be her new son-in-law), a few appearances by Joyce Barnhardt, a fire in Steph's apartment which does not reach her indestructible 70s-painted bathroom, and a secondary FTA. Junior Turley is a flasher with a regular route (and yes, Grandma Mazur is a regular) whose capture is up there with Punky Balog. Not only is there the unsuccessful attempt to capture him during a funeral with Grandma's help, but there's also why he was arrested. It's middle-of-the-pack Plum, but still funny enough that reading it in public is a risky endeavor.