This came out of the oven tonight. I baked it using a pain de mie pan, which we bought at the King Arthur Flour store some years ago. The pan has a metal lid which forces the loaf into the square shape. I'll slice it and freeze it so we can have almost fresh baked bread til we run out.
I didn't really use a recipe, just the basic four (yeast, flour, salt, water) and some butter. (See the big picture.)