The "Common European Framework of Reference for Languages" (CEFR) has prompted much reflection on language testing and raised awareness of the importance of standardisation in assessing English for academic and professional purposes in an increasingly globalised world. Criticism has nevertheless been levelled at CEFR profiles for being overly general. Such objections may derive from a misperception of the original intention of the CEFR, which was not to provide a prescriptive blueprint. Rather, its purpose was to offer consistently described descriptors to serve as a reference for assessment: teachers and assessors would then be able to use selected material from the framework to create language profiles for use in local and larger contexts. This article discusses a preliminary investigation of advanced writing produced by one student population and offers an interpretation of the CEFR overall writing descriptors with particular regard to the complexity of language which emerges at levels C1 and C2. It describes a qualitative analysis of a small corpus of learner essays written by Italian undergraduate students in response to one writing task, and describes syntactical, lexical, discourse and interpersonal features found in scripts assigned to levels C1 and C2. The purpose of this study is to identify features which may be representative of writing at these levels and use this information as a starting point to develop detailed level descriptors for institutional use.