Pound Cake gets her name from the pastry of the same name, she gets this name as a reference to her pastry based appearance, as well as a play on words, as "pound", when used as a verb, means to beat or strike repeatedly.
Her name may also be a reference to Night Caps' small size, being so small, they weigh no more than a pound.
Pound Cake is one of the more difficult battle leaders to deal with, as she tends to use her abilities a lot, especially Casting Shadows and Shadow Sneak. One of the best ways to deal with her is to use the Super Brainz with the Fearless upgrade and attack her with the Heroic Fists, as meleeing her is actually much more effective than attacking her at range. This is because despite her tendency to vanish with her abilities, she usually won't move that frequently, which allows for a relatively easy pursuit when she pops back up somewhere else, as well as due to her small hitbox size, which makes it difficult to fire at her. The Fearless upgrade allows you to prevent yourself from getting vanquished when surrounded by enemies or approaching her, as enemy attacks on PvE are weak enough that this upgrade can actually recover your health quicker than they deplete it.
If you're trapped inside her Casting Shadows dome, use the Hyper Jump Thump to try and escape from it, and if she tries to use her Fung Fu, either do the same thing or use the Super Ultra Ball and aim it to the ground. This can lower her health by a lot if it hits her close enough.
Be wary of the Hypno-Shrooms and Night Caps that spawn alongside her. The Hypno-Shrooms could be a great annoyance, especially if you're trying to hit Pound Cake close range and they're surrounding her. Her Night Caps could also add more trouble as they will try to shoot at you frequently.
Also note that rarely, a Hypno Sunflower Queen could spawn in her aid. Be wary of her because she can cause a ridiculous amount of annoyance, and with her on the field, there is also a chance that Champion Sunflowers could come in as well. This means that the Sunflowers could potentially heal either Pound Cake or the Hypno Sunflower Queen if not dealt with early on.