how/what about that!

how about that(, then)

Used to indicate that one finds something to be very interesting, exciting, surprising, or respectable. Said as an exclamation, rather than a question. A: "I heard Janet is running for a seat in the Senate." B: "Wow, how about that!" Well, how about that—the government actually passed a tax bill that the majority of Americans support!
See also: how

how/what about ˈthat (, then)!

(informal) used for expressing surprise, praise, great respect, etc: ‘Have you heard Jane’s been offered a film part in Hollywood?’ ‘Well, how about that, then!’
See also: how, what