Of course, I had 'The Wind in the Willows' as a child. I truly wish I'd had this story as well. It's less well known - but I'm not sure why.
This is a truly wonderful story-within-a-story: two children, fancying that the snow tracks they've followed from their yard are those of a dragon, encounter a kindly neighbor, who tells them a story - of course, about a boy who meets a literarily-inclined, and unusually good-tempered dragon.
Whimsical, warm and clever.