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 while the grill heats.
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.
03 - Grill the mushrooms for 3–4 minutes per side until tender with distinct grill marks, basting occasionally with any leftover marinade.
04 - Melt the butter in a large skillet over medium heat. Add the grilled mushrooms and sauté for 2–3 minutes, stirring occasionally, until fragrant and lightly browned.
05 - Remove from heat. Sprinkle with fresh parsley and adjust seasoning with additional salt and pepper to taste.
06 - Serve warm with lemon wedges on the side if desired.