HIIT during bulking phase ...

[AndsX]

Will doing HIIT once or twice a week be beneficail when trying to bulk up lean mass?

Based on my research so far it looks beneficial? Anyone doing this?

 

[Cynical Simian]

Yes. As you've probably already read, it'll improve nutrient partitioning, and with a caloric surplus (and the usual assumption/warning about appropriate pre-/post-HIIT nutrition) you shouldn't have to worry about its impact on recovery.