It's darn hard in initially confused lesson naming writer of A Midsummer Night's Dream (11)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

definition: Felix Mendelssohn composed music for A Midsummer Night’s Dream [wiki] MEND=”darn”; plus H (hard) in LESSON with just the first two letters jumbled/swapped (a sort of anagram, but only “initially confused”)