Preheat oven to 450 degrees Fahrenheit. In a medium-large stockpot, melt butter and saute all the onions (except 1/4 cup of the scallions), basil and black pepper. When onions are tender, add the flour and stir until smooth. Cook for 1 minute; add consomme, cream and wine. Bring to a boil and then turn down to a simmer; stir for 10 minutes to prevent the bottom from burning. Ladle the soup into the hollowed out onions or into crocks. Top each bowl with a crouton and 1 slice of Swiss and 1 slice of Gruyere. Place bowls in the oven until the cheese is melted and golden brown.
Remove from the oven and garnish with the remaining 1/4 cup scallions.
Special notes
Recipe provided by the National Onion Association
Courtesy of Chef Jeffrey Galick; Harraha's Steak House, Reno, Nevada 2010