Onion soup served with melted cheese and crusty bread (on top or on the side) will make for a hearty lunch. The same with a summer garden salad or a side dish of roasted winter root vegetables will make dinner.
Use medium size white or yellow globe-shaped onions for strong flavor or large flat onions—called Bermudas—for a mild flavor.
Step One. The ratio of sliced onions to liquid—chicken or beef stock—will be in the range of 1:1–that is one cup of thin sliced onions to one cup of liquid. (One medium size onion will make a cup sliced.) This ratio can vary; you can certainly add more onions if want a fuller onion flavor (a ratio of 3:2). Each cup of liquid will equal about one serving.
Use medium size yellow or white globe onions—they will keep their oniony flavor after cooking; use Bermuda onions for sweeter flavor. Cut the onions in half lengthwise and then cut across the grain into slivers.
Warm 2 or 3 tablespoons butter in a saucepan or stock pot over medium-low heat. Stir in the onions and a pinch or two of salt (or a pinch or two of sugar) and cook them uncovered slowly and evenly until they are soft and melting and just beginning to turn golden. Stir occasionally to prevent sticking. Depending upon the amount of onions you are cooking sauté the onions between 12 and 30 or more minutes.
Step Two. Add just warm chicken stock (or beef stock) to the pot and seasoning to taste (such as bouquet garnie: 2 bay leaves, 2 sprigs thyme, 4 sprigs flat-leaf parsley, 2 sprigs tarragon tied with string). Turn the heat to medium-high and bring to a boil then turn the heat down to a simmer (the liquid will send up a few bubbles at a time). Add salt and fresh ground black pepper to taste. Also add a bit of grated raw onion if you like, and for a very hearty soup add 2 or 3 medium carrots scraped and cut into thin julienne (1/8 inch thick and 2 inches long). Cover and simmer for 20 to 40 minutes or more tasting for flavor as it cooks. Flavors well-blended is your goal.
Step Three. Crusty French bread sliced and coarsely grated cheese–Gruyère, Camembert, or Swiss—can be served on the side or in the soup.
Cut the bread into slices about 3/8 inch thick; halve a clove of garlic and rub each side of the bread with garlic then brush each side with olive oil. Toast the slices on a baking sheet in the oven (at 325°F) or under the broiler until just crisp and golden brown.
Ladle the hot soup into the bowls and serve immediately. Additional grated cheese can be added to each bowl as desired.
Alternatively, rather than breaking the bread into small pieces you can cut slices just enough to cover the top of each serving crock. Ladle hot soup into each crock, fit the bread slices in place, sprinkle cheese on top, dribble a bit of olive oil over each, place the crocks in a roasting pan or on a sturdy baking sheet and place under the broiler or bake for 6 to 10 minutes until the cheese melts or bubbles and lightly browns, then serve right away.
If you don’t plan to serve the soup immediately it can be covered and refrigerated for two days before reheating or it can be frozen for a few weeks.