Pierre’s Four-Onion Soup

Pierre Moulin makes this soup whenever he is homesick for his native France, even though the scallions, leeks, and shallots crept into his recipe after he moved here and opened Pierre Deux Antiques in Greenwich Village nearly 30 years ago. He serves the soup with a platter of cold sliced beef, parslied potatoes, mustard, and horseradish.

Ingredients
3 tablespoons olive oil
I pound yellow onions, sliced
1/2 cup well rinsed, sliced white part of leeks
1/2 cup sliced light green part of scallions 1
1/2 cup sliced shallots
I teaspoon sugar
I teaspoon salt
3/4 pound Swiss cheese, grated
6 cups Savory Beef Stock
sourdough bread, sliced into 6 thick rounds

Directions
Preheat the oven to 350'F.
Heat the oil in a large heavy skillet or Dutch oven over medium low heat Add the onions, leeks, scallions, and shallots and stir constantly until the onions are translucent, 5 minutes.
Add the sugar and salt, increase the heat to medium high, and continue stirring until the onions caramelize, 15 minutes. They will be golden brown but still moist.
Divide the onions among 6 ovenproof soup bowls. Sprinkle some of the cheese over the onions, reserving some for the tops. Ladle in the beef stock. Place a slice of bread on top of each serving and sprinkle with the remaining cheese. Bake in the oven until golden, 20 to 30 minutes. Let sit for 10 minutes before serving,