This paper presents a design for extensible records in Scala satisfying design goals such as structural subtyping, type-safe polymorphic operations, and separate compilation without run-time bytecode generation. Using new features of Scala 3, the design requires only minimal, local changes to the Scala 3 reference compiler Dotty as well as a small library component. Runtime performance is evaluated experimentally using a novel benchmarking suite generator, showing that the design is competitive with reflection-based approaches for structural field access, and excels at immutable extension and update operations.