it is a VERY old expression (17th century) which means exactly what you say. However you would only come across it now in an historical novel, and if you asked the average (or even above average) native speaker about it you would get a blank look (disclaimer: I had to look it up!)

This is even more interesting, especially for Chinese students who are unfamiliar with English eating habits in previous centuries. It explores the origins of the saying. http://www.phrases.org.uk/meanings/fine-words-butter-no-parsnips.html A footnote: Britain has now become a nation of foodies and London is one of the greatest culinary capitals of the world. The British cook and eat very well now. So perish the thought that British food is awful and that the British do not know about the fine art of food and wine.

It's not an idiom I've ever heard, but yes, that's how I'd interpret it.

Hilary, thank you so much for a good response, as always. Nowadays on the internet, there is layman or fan research on everything. Here is a fan review of the Downton episode in question: Downton Abbey Season 5, Episode 3: Sympathy Butters No Parsnips. http://geekmom.com/2015/01/downton-abbey-season-5-episode-3/ Please enjoy. What, I wonder, butters the parsnips best? Money, sex, power, or, praise be to God, love?