Apple pie order
Tidy and well-ordered.
The phrase may originate from the French 'nappes pliees' = neatly folded, or from 'cap-a-pie order'. There's no definitive evidence to support this and the origin remains uncertain.
It is recorded first in English in Sir Thomas Pasley's Private Sea Journals, 1780:
"Their Persons Clean and in apple-Pie order on Sundays."