1
1 cup balsamic vinegar
1/2 cup malt vinegar
1/3 cup Worcestershire sauce
3 tbsp tomato paste
1 tbsp brown sugar
2 tsp garlic powder
2 tsp onion powder
1/2 tsp salt
1/4 cup port
To make Port steak sauce: Boil balsamic vinegar in a large, wide frying pan over high until reduced by half, 2 to 3 min. Add remaining ingredients to pan. Continue boiling, whisking often, until slightly thickened and reduced to 1 cup, 2 to 4 more min. Cool completely.
To make Port grilled mushrooms: Preheat barbecue to medium-high. Grill whole mushrooms until cooked through, basting often with Port Steak Sauce. Transfer to a platter and sprinkle with chopped parsley.