Ingredients

• 2 tablespoons clarified butter, plus more for toasting
• 1/2 Spanish onion, sliced
• 1 cup sliced cremini mushrooms
• Salt
• 4 thick-cut slices rye bread
• 8 slices mozzarella
• 10 ounces sliced cooked brisket
• 1/4 cup Steak Sauce, recipe follows
• 2 tablespoons extra-virgin olive oil
• 4 cloves garlic, ground
• 2 shallots, ground
• 1 portobello cap, ground
• 1/2 cup Worcestershire sauce
• 1/4 cup balsamic vinegar
• 2 tablespoons ketchup
• 2 tablespoons brown sugar
• 1 teaspoon Dijon mustard
• 1 teaspoon salt
• 1/4 teaspoon chili powder
• 1/8 teaspoon ground allspice
• 2 tablespoons dark soy sauce
• 1 tablespoon molasses

Instructions

1. On a hot griddle, add the clarified butter, and then add the onions. Cook until just tender, and add the mushrooms. Season with salt, and cook until caramalized. Set aside to cool.
2. To assemble the sandwich, top one slice of the bread with 2 slices of mozzarella, 5 ounces sliced brisket, 2 tablespoons of the Steak Sauce, half of the caramelized onions and mushrooms and 2 more slices of mozzarella, then top with another slice of bread. Repeat for the remaining sandwich. Ladle some clarified butter on the griddle and place the sandwiches in the butter. Cook the sandwiches on both sides until the bread is toasted, the meat is warm and the cheese melts.
3. Heat the oil in a medium saucepan set over medium-high heat. Saute the garlic, shallots and portobello for 3 minutes. Add in the Worcestershire, vinegar, ketchup, sugar, mustard, salt, chili powder and allspice. Simmer for 15 minutes. Add 2 cups water, and then cook for 10 minutes. Add in the soy sauce and molasses, and cook for 5 minutes. Blend until smooth and cool.