Winter veggie beds

A thought came into my head while reading a thread on year long growing. I had read an old book a few years ago, can't remember the name, but it was about organic gardening. There were different stories about different people and there organic farms.

This book was maybe from the 60's or 70's. Anyways one of the men in the book would grow some crops, I can only remember carrots right now. Before the snow came he would cover his beds with leaves, real thick like. The snow would fall and cover the leaves and beds.

He then said he would go out to the beds during winter, reach through the snow and leaves and pull out fresh produce, undamaged by the cold.

Has anyone done this? Seems like you could get extra crops in by doing this. Just sharing thoughts, if anything.