'Apple-pie order!' said Mr Boffin, after checking off each inscription with his hand, like a man beating time. 'And whatever you do with your ink, I can't think, for you're as clean as a whistle after it. Now, as to a letter. Let's,' said Mr Boffin, rubbing his hands in his pleasantly childish admiration, 'let's try a letter next.'

      Charles Dickens, Our Mutual Friend

This phrase might not be as American as apple pie, Halliwell's Dictionary defines how it's used today in familiar conversations in both England and the United States to denote that everything is in its proper place. Some synonyms for this adjective would be orderly, regular; in order, in trim ; neat, tidy, well regulated, correct, methodical, uniform, symmetrical, shipshape, businesslike, systematic; and unconfused. Something akin to getting all your ducks in a row; extreme neatness.

Here's some flaky etymology about this mock food eponym. Some sources suggest this phrase for prim and precise order is cap-à-pie, like a knight in complete armor from head to foot Shakespeare uses this idiom when he has Horatio describe Hamlet's ghostly father as armed cap-a-pie. The French call nappes pliées, meaning "folded linen" which gives the image of neat as folded linen and perhaps is nearer to the mark. Most experts say it may stem from nap-pe-pli; both French phrases nappes pliées and cap-a-pie suggest the minute attention to detail.

It has also been suggested that "Apple-pie order" could be a corruption of alpha, beta, meaning as orderly as the letters of the alphabet. While others say that that apples made into a pie are quartered and methodically arranged when the cores have been removed. During colonial times apple pies were made by carefully arranging apple slices in a highly stylized, vertical pattern and then hidden under a crust of dough.

Short story writers Jack London and Mark Twain liked this cliché too. In 1874 Ann Taylor used it in her Children's Literature:

    Now there was an old fellow much famed for discerning,
    (A drake, who had taken a liking for learning),
    And high in repute with his feathery friends,
    Was called Dr Drake: for this doctor she sends.

    In a hole of the dunghill was Dr Drake's shop,
    Where he kept a few simples for curing the crop,
    Small pebbles, and two or three different gravels,
    With certain famed plants he had found on his travels.

    So, taking a handful of suitable things,
    And brushing his topple and pluming his wings,
    And putting his feathers in apple-pie order,
    He went to prescribe for the lady's disorder.

    "Dear Sir," said the Duck, with a delicate quack,
    Just turning a little way round on her back,
    And leaning her head on a stone in the yard,
    " My case, Dr Drake, is exceedingly hard ! "

    "I feel so distended with wind, and opprest,
    So squeamish and faint, such a load on my chest;
    And, day after day, I assure you it is hard
    To suffer with patience these pains in my gizzard."

And yet another etymologist claims the phrase for being tidy and well-ordered originated in England, was first coined in 1813 by Sir Walter Scott and has nothing to do with apple pies at all really. Most do agree that it's a corruption of the French phrase nap plié which sounds a lot like apple pie.

Have your friends ever short sheeted you? Well here is a little trivia! It also accounts for apple-pie bed, you know the practical joke where your friends sneak in and double your sheets up like the cover of an apple turnover so when you climb into bed you can’t get your legs stretched out.

Sources:

Apple-pie Order.
www.bartleby.com

The Autobiography and Other Memorials of Mrs Gilbert, Formerly Ann Taylor:
digital.library.upenn.edu/women/taylor/ autobiography

BREWER: Dictionary of Phrase and Fable, 57-58:
www.bootlegbooks.com/Reference/ PhraseAndFable/data/57.html

thesaurus.com:
www.thesaurus.com/thesaurus

xrefer:
www.xrefer.com