In season 1, episode 3 the Super Hero Girl team attempt to save a bakery from destruction (unsuccessfully). At the end of it Batgirl draws the correlation that Lex Luthor is behind it. Supergirl then poses the question, "Lex Luthor is like, the richest man in Metropolis. What could Lex Luthor possibly have against cupcakes?". This is very likely a reference to the internet meme spawned from a children's counting book depicting Lex Luthor stealing 40 cakes, despite being the richest man in Metropolis, thus having no need to steal cakes in the first place.

Edited from DC Super Hero Girls: Sweet Justice (2019)