ABSTRACT Existing research on EU legitimacy has neglected one aspect – the transformation of EU strategies into concrete national plans. This article reflects on this gap by analysing the throughput legitimacy of the implementation of the ambitious and transformative Next Generation EU (NGEU) plan into national strategies, called Recovery and Resilience Plans (RRPs), in four Central and Eastern European countries. Focusing on the transparency, accountability, openness and inclusiveness of the RRP elaboration process, it finds that the elaboration process suffered from shortcomings in all aspects analysed. In particular, they affect the quality of legitimacy of the process of implementation. The article found that while the formal aspects of throughput legitimacy were present, most of the factors that create a mirror that shows how actors participated, how their comments were addressed or how the parliamentary role was respected failed in almost all cases. This finding has implications for research on throughput legitimacy, which should focus more on its quality than on its procedural parts.