Mighty Isis, an obscure DC comics heroine, takes a pie in the face in an issue of her short-lived series from the 1970s. I posted the entire tale, explaining the context of why a superhero is getting pied, on my Tumblr. It's a nicely drawn pieing, though! I remember this from when I was a kid, and I found the issue a while back in a "random back issues" box at a local comics store.
"Spl-lat" is a pretty good onomatopoeia for a pie hit, by the way. When I'm on the receiving end of a pie in my face, what I usually hear is a muffled 'splat' sound. (Then more splatting as excess pie falls onto the floor.)