Good/Bad English

[David Gilbert]

Essentially, yes, but, for instance, if you wanted a smaller helping of mash you'd ask for less potatoes rather than fewer potatoes, because you're talking about mass rather than number.

Funny I would always use mash potato as singular so it terms of quantity I'd ask for less mash potato, but what do I know?

[Richard James]

Essentially, yes, but, for instance, if you wanted a smaller helping of mash you'd ask for less potatoes rather than fewer potatoes, because you're talking about mass rather than number.

Funny I would always use mash potato as singular so it terms of quantity I'd ask for less mash potato, but what do I know?

Yes, you could do that as well: less mash or less mash(ed) potato would also be fine.

[Greg Breed]

It sounds to me like you could go around in circles with this topic. Mash is made up from more than one potato (usually) and ends up as a single lump. So it goes from plural to singular. You could ask for "less mashed potato" or "fewer mashed potatoes" and both would be correct. I imagine most people would use the former though.

[Brendan O'Gorman]

What this thread needs is less pedantry and fewer pedants.