The phrase "a single portion of" is correct and usable in written English.
It can be used when referring to one specific part or serving of something, often in contexts related to food, data, or analysis.
Example: "For the experiment, we will analyze a single portion of the sample to ensure accuracy in our results."
Alternatives: "one serving of" or "a solitary piece of".
A single portion of charcoal to cook a meal costs at least 20 shillings (23 cents).
Recycling studies showed that a single portion of the catalyst could be used for six successive times with no apparent loss of activity.
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.
But Hazare's asceticism – he eats yoghurt for breakfast, chapatis and a single portion of vegetables for lunch and has just a glass of lemon juice for dinner – has a deep resonance in a time when unbridled materialism is the dominant social ethic.
The shrimps - no bigger than a thumbnail - then must be carefully peeled, a tedious task best left to the experts: it takes an experienced peeler about 10 minutes to shell a single portion of the baby shrimps, which, no doubt, will be downed in a few highly savored bites.
We shared a single portion of cheese, and even though we hadn't exactly hidden the fact that we were writing a review, what with the two notebooks and all, the serving was so meagre we could have read our notes through each wafer-thin slice.
(Canadian tar sands are the largest single portion of those foreign reserves).
Food waste is the largest single portion of solid waste cramming American landfills.
Rather than increasing the size of every component of a meal, an interesting question is what response would there be to a larger portion of a single component of a meal, both within a meal and subsequently.
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.
