Buternut or Butternut: How To spell?
The word Buternut is misspelled against Butternut, a noun meaning "An American tree (Juglans cinerea) of the Walnut family, and its edible fruit; -- so called from the oil contained in the latter. Sometimes called oil nut and white walnut."
Butternut has double "tt" is mispronounced as "t"Remember double 'TT' in between the strings bu & ernut which should not be misspelled with single 'T'
Wrong Spelling:  bu-t-ernut  Correct Spelling:  bu-tt-ernut 
Check more misspelled words of Butternut to spell it correct.