"Once in a while" OR "Once in awhile"? [duplicate]
Solution 1:
The correct phrase is "Once in a while", as two separate words.
As "awhile" is an adverb, it wouldn't make sense to say "Once in awhile". See @V0ight's comment:
Replace 'awhile' with any other adverb, like 'rarely' or 'seldom' and you'll see it makes no sense. 'Once in rarely'? 'Once in seldom'?