Black Tap's Steak Au Poivre Burger Recipe

Ingredients

• 1 1/2 tablespoons unsalted butter (1 tablespoon at room temperature)
• 1/2 medium spanish onion
• 2 tablespoons drained green peppercorns in brine
• 2 tablespoons Shaoxing cooking wine
• 1/2 cup heavy cream
• 1 teaspoon apple cider vinegar
• 1 teaspoon worcestershire sauce
• 1 teaspoon Kitchen Bouquet or Gravy Master
• 1/4 cup crumbled blue cheese
• 2 pounds 20 percent lean ground beef
• 1 tablespoon kosher salt
• 1/4 teaspoon freshly ground black pepper
• 2 teaspoons canola or vegetable oil
• 4 4-inch potato buns
• 1/2 cup crumbled blue cheese
• Lettuce, tomato slices, pickle spears