01 - In a large bowl, whisk together olive oil, balsamic vinegar, minced garlic, thyme, rosemary, salt, and pepper. Add the mushrooms and toss to coat evenly. Let marinate for 10 minutes.
02 - Preheat an outdoor grill or grill pan to medium-high heat. Thread the mushrooms onto skewers or place them in a grill basket for easier handling.
03 - Grill the mushrooms for 3 to 4 minutes per side until tender with distinct grill marks, basting occasionally with any remaining marinade.
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 from heat. Sprinkle with fresh chopped parsley and adjust the seasoning with additional salt and pepper to taste.
06 - Transfer to a serving dish and serve warm with lemon wedges on the side if desired.