01 - In a large bowl, whisk together olive oil, balsamic vinegar, minced garlic, thyme, rosemary, salt, and pepper. Add mushrooms and toss to coat evenly. Marinate for 10 minutes while you heat the grill.
02 - Preheat an outdoor grill or grill pan to medium-high heat. Thread mushrooms onto skewers or place in a grill basket.
03 - Grill mushrooms for 3-4 minutes per side, until tender and marked with grill lines, basting occasionally with leftover marinade.
04 - Heat butter in a large skillet over medium heat. Add 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 salt and pepper to taste.
06 - Serve warm with lemon wedges on the side if desired.