INGREDIENTS

• 2 tablespoons olive oil, divided
• 3 cups sliced onions (about 2)
• 3/4 cup Cabernet Sauvignon or other dry red wine
• 1 pound ground bison (buffalo)
• 2 tablespoons chopped shallots
• 1/4 teaspoon coarse kosher salt
• 1/4 teaspoon dried thyme
• 4 organic hamburger buns
• 6 ounces sliced Wisconsin white cheddar cheese
• Dijon mustard
• 1 small head of escarole, leaves separated

PREPARATION

Heat 1 tablespoon oil in heavy medium skillet over medium- high heat. Add onions, sprinkle with salt, and sauté until tender and golden brown, stirring often, about 10 minutes. Reduce heat to medium and continue to sauté until very tender and well browned, about 15 minutes longer. Add wine and cook, stirring occasionally, until liquid is absorbed, about 5 minutes. DO AHEAD: Can be made 3 days ahead. Cool, cover, and chill.