Cornmeal and Buckwheat Flour Polenta

I encountered dark polenta a great many years ago when my husband, who was then an advertising whiz, invited me to join him in Valtellina, in northern Lombardy, where he was shooting a television commercial. It is not a popular polenta in Venice, where we have long lived, and it had slipped out of mind until I became acquainted with a woman—the same one who gave me the correct procedure for making the risotto with spinach—who was from Sondrio, in Valtellin