The recent Covid-19 pandemic has forced HEI to quickly adjust their approach to teaching and learning by massively adopting, basically overnight, approaches based on digital learning. Covid-19 gave a huge impulse to the spread of digital tools and the consequent literature is rich in details and information about more and less successful experiences with digital learning. This unexpected 'experiment' exposed the effectiveness and efficiency of well-conceived learning strategies that blend digital and traditional learning approach. While blended learning per se is an established discipline, a unified framework to go from theory to practice is still elusive. Given the above, the knowledge developed and acquired during the pandemic has a huge potential to reveal what are the features of a good blended learning strategy in different educational situation. This work aims at investigating what would be an optimal blended learning strategy for program design in the context of engineering education. The contribution is based on a focus group discussion involving teacher from 6 different European HEI and results indicates that the level of understanding, as presented in the Bloom taxonomy, of the focal activity and the correct balance between the educational and social dimensions of student's university life are the two critical drivers for blended learning design. The study confirms also the main findings in literature, related to the use of digital tools before and during the pandemic and suggests that the Covid-19 had a positive impact on the readiness to adopt digital tool of HEI. Finally a few problems experienced in the post covid phase are presented along with the identified future directions of research.