01 - In a large bowl, whisk together the olive oil, balsamic vinegar, minced garlic, dried thyme, dried rosemary, salt, and black pepper. Add the cleaned mushrooms and toss thoroughly until evenly coated. Let marinate for 10 minutes.
02 - Preheat an outdoor grill or grill pan to medium-high heat. Thread the marinated mushrooms onto skewers or place them in a grill basket for easier handling.
03 - Place the mushrooms on the grill and cook for 3 to 4 minutes per side, until tender with distinct grill marks. Baste occasionally with any remaining marinade during grilling.
04 - Melt the butter in a large skillet over medium heat. Add the grilled mushrooms and sauté for 2 to 3 minutes, stirring occasionally, until fragrant and lightly browned.
05 - Remove the skillet from heat. Sprinkle the chopped fresh parsley over the mushrooms and adjust the seasoning with additional salt and pepper as needed.
06 - Transfer to a serving dish and serve warm alongside lemon wedges if desired.