Bizcochito literally translates to "little biscuit" or "little sponge cake." The -ito suffix is a diminutive, often used in Spanish to denote something small, cute, or endearing.
In slang, it's a common term of affection, similar to "sweetie" or "cupcake." In this song, however, Rosalía flips the meaning on its head. She sings, "Yo no soy y ni vi'a ser tu bizcochito" (I'm not and never will be your little cupcake), using this seemingly sweet word to make a powerful statement about refusing to be seen as a passive or delicate object.
ROSALÍA is not here to be anyone's sweet little treat. That's the message right from the start of this super short, super confident track. She repeats, "Yo no soy y ni vi'a ser tu bizcochito" (I'm not and I'm not going to be your little cake). She rejects being seen as something small or cute, instead declaring she has "to' lo que tiene delito" (everything that's a crime). It's a bold statement about her own power and appeal, and she's not afraid to say it.
She brushes off any hate coming her way, saying "El mal de ojo que me manden me lo quito" (I remove any evil eye they send me). The song is full of these confident lines. She claims her success isn't luck, it's earned: "No basé mi carrera en tener hits / Tengo hits porque yo senté las base'" (I didn't base my career on having hits / I have hits because I laid the foundations). She's in control, and she wants everyone to know it.