The phrase "a single portion" is correct and usable in written English.
It can be used when referring to one specific serving or amount of something, often in contexts like food or resources.
Example: "For this recipe, you will need a single portion of pasta for each serving."
Alternatives: "one serving" or "a solitary amount".
A single portion of charcoal to cook a meal costs at least 20 shillings (23 cents).
It is very economical to make and a single portion would cost well under £1 in Manila, depending on the amount of meat included.
Like a Thanksgiving turkey, cassoulet brings people together by virtue of sheer volume; no one has ever made a single portion.
If you're in the mood for some post-show chow, the Original Hotcake House (1002 Southeast Powell Boulevard) just around the corner will gain you five pounds in weight in a single portion – and it's open 24 hours.
Sold as a single portion, that bottle packs in 240 calories – nearly 10% of an average man's daily recommended calorie intake and 130% of his added sugars for the day.
And to round out the listed savory dishes, a single portion of lamb slow cooked to a velveteen texture, bright red within, over a sauce of miso and espresso.
Traditionally, bento is a single-portion meal, served in a box that contains small amounts of several types of food.
So a single-portion pack may indeed often be the greener consumer choice – but only if we are really sure we need that stuff inside.
This season's tool is cedar paper, six inches square and pliable enough to embrace a single-portion fillet of salmon, a hunk of fresh mozzarella or half a ripe summer peach.
It follows that either the Kripkean argument is incorrect, or replacement of even a single part (or small portion) does not preserve identity (a view known as "mereological essentialism;" Chisholm 1973).
The problem is that of reconciling the intuition that certain small changes (replacement of a single part or small portion) preserve identity, with the problem illustrated by the sandals example of §2.5.
