* While you can slice onions by hand, I like to do them in my Cuisinart (food processor) using the slicer disk. You can also use a mandoline for slicing.
* Soup freezes well. Let cool and transfer to a freezer-safe container.
* Instead of serving with crusty bread you can substitute homemade croutons. Take 4 slices of day-old rye bread (or other bread), remove crusts and cut bread cut into ½-inch cubes. In a heavy skillet melt 2 tablespoons butter over moderate heat, add bread cubes, and cook them, stirring, until they are golden, about 5 minutes. Place on top of soup and cover with cheese.
* Serve with grilled or pan-fried sausage for a simple winter dinner.