This page uses data from the Miitopia Param Info spreadsheet, compiled by PibPasquale, Kobazco, and UglyFrenchFry.
The Hamburger ★★ is a massive beef patty complete with lettuce, tomato, white onion, cheese and bacon. They're all sandwiched between two seeded buns and served on a white, crumpled piece of wax paper.
(Has sparkles, only V. Rare foods have this.)