Gorgonzola Stuffed Burgers

Bahan-bahan (4 porsi)

• 2 pounds ground beef
• 1½ teaspoons salt
• ½ teaspoon freshly ground black pepper
• ½ cup crumbled gorgonzola cheese
• 3 tablespoons unsalted butter
• 1 medium shallot, (minced)
• 2 teaspoons minced fresh thyme
• ½ ounce dried porcini mushrooms, (soaked in one cup of hot water for 20 minutes, squeezed dry and minced (save the soaking liquid!))
• ½ pound shiitake mushrooms, (stems removed and thinly sliced)
• ½ pound cremini mushrooms, (sliced)
• 3 tablespoons brandy or cognac
• salt and freshly ground black pepper, (to taste)
• ¼ cup olive oil
• 4 large red onions, (thinly sliced)
• ¼ cup brown sugar
• 2 tablespoons red wine vinegar
• 2 tablespoons heavy whipping cream
• salt and freshly ground black pepper, (to taste)
• 4 hamburger rolls