bogglingly

adverb2

1. •
   In a stupefying manner or to a stupefying degree.

   • It was bogglingly complex, with 212 speaking parts, more than 1000 camera setups, 95 scenes, 15 separate film stocks, and endless intercuts and flashbacks -- "everything but footnotes," Stone joked. — 1992
2. •
   While boggling; with an amazed expression.