"A Dish of Orts" was a thing I had never heard of,
until I was studying the writings of George MacDonald (19th century).
MacDonald published many titles during his long life.
He gave the title "A Dish of Orts"
to a collection of his own essays in standard English.

For the title alone, I had to look up whatever I could find
about Scots to see what it meant.

The Online Scots Dictionary:

"ort":   verb
to reject, throw away, refuse, to deal wastefully with food,
as by picking out the best parts and casting aside the rest, or by crumbling it,
to pick out what is to be rejected, to pick and choose,
to distribute wastefully and extravagantly.

"Orts": noun, plural
What is useless and has been cast aside,
leavings, leftovers.   


A book labelled "A Dish of Orts," therefore,
is a collection of odds and ends of writing,
none of which is sufficient for an entire book in itself.
MacDonald exploits the English / Scots combination here
that served him well in his literary career:

he would not, as a mature adult,
return to Scotland permanently,
where he had been born and raised;
but he would proudly identify himself as a Scot born and bred
who chose to be a satellite in London's orbit.

If you're curious:
A Dish of Orts