small onions, thinly sliced
cans (14 ounces) low sodium beef broth (recommended: Swanson's)
cans (10 ounces) beef consomme (recommended: Campbell's)
packet onion soup mix (recommended: Lipton's)
slices French bread, about 1 inch thick
cup shredded Gruyere
Combine onions, broth, consomme, and soup mix in a slow cooker. Cook on HIGH setting for 4 hours, or LOW setting for 8 hours. Ladle soup into serving bowls. Top with a slice of French bread. Sprinkle 2 tablespoons cheese over each bread slice. Put soup bowls under broiler until cheese is melted. Alternatively, place the bread on a baking sheet and top with cheese; broil until cheese has melted, about 30 to 40 seconds, and set on top just before serving.