I Transmigrated Into a Book and Mistook the Female Supporting Character, Dear

When a girl who is lacking in every way and a complete disaster transmigrates into the role of the supporting female character in a book called The Scatterbrained Girl Who Fell for the Billionaire CEO

(That's right, the supporting character, not the heroine)

The supporting character's first words upon meeting the heroine:

"Put down that cake. Let me handle it."

The supporting character's first words upon meeting the hero:

"Sir, that egg tart is mine. If you dare steal it... Heh heh, your grandma in the underworld is watching you from the ferry!"

Seriously, did the supporting character walk onto the wrong set or what? Hey!

Also known as The Disaster of a Supporting Character Is Truly in Love with Food, and The Heroine Cries, "This Isn't My Supporting Character!"