Energy has been at the core of the EU integration since its inception. However, following the path of a shooting star, the key role of energy gradually declined over time, to the level of being basically left out from the Treaties, at least up to Lisbon. The EU has struggled to circumnavigate this “energy-gap” of the Treaties by legislating on energy-related issues by making use of its shared competences in the areas of internal market and environment. However, this effort has resulted in a very fragmented EU energy policy, also characterized by the absence of a major element: security of energy supply. After the 2014 Ukraine crisis a new momentum has emerged in the EU about the urgent need of creating a truly European energy policy, with both the new President of the EU Council and the new EU Commission calling for the creation of a EU Energy Union. This paper argues that the EU should seize this historical opportunity to fill the main long-lasting gap of its energy policy: security of energy supply. To this end, the paper proposes a set of new actions that might be undertaken in this field, also outlying that the most feasible option to the development of a new EU Energy Union seems to be the formation -through a scheme of differentiated integration- of a smaller coalition of Member States committed to quickly advance the integration of their energy policies under the principle that only by acting together the EU will be able to meet the growing energy challenges of the future.