Recipe of the Week: French Onion Soup Gratin

Nothing beats the fragrant taste of a steaming cup of deliciously sweet onion soup, no matter what the weather is outside. I like to make it in large batches and then save it in the freezer for a quick meal. Serves eight. (Chef tip: For a sweeter taste, roast your onions at 350°F for 45 minutes wrapped in foil with the top and bottom cut off and peeled.)
1/4 cup unsalted butter
2 tablespoons extra-virgin olive oil
6 onions, chopped
2 cloves garlic, minced
1 tablespoon sherry wine
1 tablespoon cognac
1 quart defatted beef stock
1 teaspoon Worcestershire sauce
2 bay leaves
1 teaspoon sea salt
1 teaspoon freshly ground black pepper
8 crostini
4 ounces gruyere cheese, grated
1 teaspoon fresh chives, chopped
Heat the butter and oil in a large stockpot over medium-high heat. Add the onions and garlic, and cook over medium heat for 30-40 minutes, stirring occasionally, until the onions turn golden brown. If the onions aren’t browning, turn the heat up. Do not burn.
Add the sherry and cognac, scraping up the brown bits in the pan, and simmer uncovered for five minutes. Add the beef stock, Worcestershire sauce, bay leaves, salt and pepper. Bring to a boil, lower the heat, and simmer uncovered for 30 minutes. Remove the bay leaves and taste for seasoning.
Preheat the boiler and position a rack 5 inches below the heat source. Ladle the soup into heat-proof serving bowls, top with the crostini, sprinkle generously with grated gruyere, and broil for three to five minutes, until the cheese is melted and bubbly.
Sprinkle with fresh chives and serve hot.