We tried this, but the picture doesn't match up with the recipe - we also didn't shake up the prosecco in with the other two! It was interesting, but the complexity of the Strega got a bit dominated by the blue curaçao.
Your brand of blue curacao will dramatically affect colour. e.g. De Kuyper is a deeper blue than Bols. Thanks for spotting the error in "How to make" - now corrected.