Portabello and Bearnaise Burger w/ Garlic & Herb Spread

Ingredients

2 pounds ground chuck (80% lean)
1 shallot, finely chopped
2 tablespoons Worcestershire sauce
coarse salt and pepper (teaspoon of each)
vegetable oil, for brushing the grill rack
1 tablespoon olive oil
2 tablespoons balsamic vinegar
18 thick cut slices of portabello mushrooms
4 tablespoons butter
1 packet of Béarnaise Sauce Mix
¾ cup whole milk
6 soft Kaiser rolls, split
3/4 cup Alouette Garlic and Herb Spread
6 leaves of green leaf lettuce

Instructions

Preheat gas grill to medium high. To prepare the patties, combine ground chuck, shallots, Worcestershire sauce and salt and pepper. Mix thoroughly with your hands so the ingredients are evenly dispersed. Divide the mixture into six equal portions. Form into even, round patties that are slightly larger than your bun. In a small bowl, combine the olive oil and balsamic vinegar. Set aside. Brush the grill rack with vegetable oil. Arrange portabello slices on the rack as to not fall through the grates. Brush exposed side of mushrooms with oil and vinegar mixture using a pastry brush. Cook for two minutes, turn and brush the remaining side. Cook for two more minutes, remove and place in a dish covered with foil to keep warm. While the second side of the mushrooms are cooking, place burger patties on opposite side of rack. Cover and cook for 5 minutes, turn and cook for an additional 5 minutes. Remove from grill and put on a plate and cover with foil to allow them to rest. To prepare Béarnaise sauce, place a grill safe saucepan on the grill. Put butter and entire contents of Béarnaise sauce mix into the pan and whisk together until combined. Add milk. Whisk frequently and bring to a boil about two to three minutes while sauce thickens. It should be the consistency of yogurt when it is finished. While Béarnaise sauce is thickening, place buns on the free side of the grill, cut side down, until lightly toasted. Remove buns and sauce from grill. To assemble the burgers, spread a tablespoon of the Alouette spread to the cut side of each bun (tops and bottoms). Place a leaf of lettuce to cover the bottoms of each of the buns. The burger patties will be placed atop the lettuce. Each patty will be topped with 3 slices of mushroom. Spoon enough Béarnaise sauce to cover the mushrooms of each burger (about two heaping tablespoons). Add the roll tops and serve. Makes 6 burgers.