Muesli Einstein eats on a lazy morning? (3-2)
I believe the answer is:
lie-in
'lazy morning?' is the definition.
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for lie-in that I've seen before include "Extra snoozing" , "Extended bedtime!" , "time spent with crossword, perhaps" , "Extended time in bed in the morning" , "Period in bed longer than usual" .)