The phrase 'doubly interesting' is correct and usable in written English.
You can use it to describe something that is especially interesting or intriguing. For example, "The historical details of the story make it doubly interesting."
All of this is doubly interesting in light of developments in photographic technology today.
By showing the mechanics, the routine is doubly interesting, yet the magic remains intact.
That perspective makes Ms. Kennedy's play, being given a somewhat uneven production by the Classical Theater of Harlem, doubly interesting.
What makes these modernizations doubly interesting is that they live side by side with the old Nancy.
It would have been doubly interesting to see the play performed by disabled actors, but under Ralph B. Peña's direction the cast here is never less than credible.
The choice was doubly interesting because Mr. Temirkanov is known in the West chiefly for his splendid work in Russian repertory.
It was the kind of programme that made you want to reach for your iPhone, and make doubly sure that the interesting text that you had been anticipating every half an hour for about the last 15 years, had not finally landed.
Discussing epidurals with two sets of midwives proved doubly redundant but provided an interesting insight into the variations that exist.
DUI is neither, so we think that the conclusions might not apply to a doubly uniparental system (it would be actually very interesting to build a mathematical model for DUI).
** While this is interesting and somewhat accurate as literary criticism, it is doubly powerful as autobiography, given Naipaul's own willing "removal" from blackness, his yearning, as a writer from the provinces, to be seen as cosmopolitan.
It is interesting to compare the SC and OFDM systems in doubly selective channels.
