There's a book called A Year in Provence
by Peter Mayle. I'm pretty sure that's where I first came across the concept of eating garden fresh radishes with "good" butter and sprinkled with salt. So perhaps it's a French thing. I've tried it, but found it difficult to get the butter to stick to the juicy surface of freshly cut radish....
It works better for me with really good EV olive oil and a drop or two or balsamic vinegar.
It's a great novel though. Really inspires you to garden and cook and eat really