Great link, Hotdog!
I've always heard it as 'meat and potatoes' in any sense. But, grammatically, either way would be correct; culturally, 'meat and potatoes' is correct.
lol! Perhaps in Russia they are...I come from hardy farm country where 'meat' is "the" thing. In order of serving size: meat, potatoes, vegetables. That's in the American Midwest.![]()