01 - In a large bowl, whisk together olive oil, balsamic vinegar, minced garlic, thyme, rosemary, salt, and black pepper until well combined.
02 - Add the cleaned mushrooms to the marinade and toss thoroughly to coat evenly. Let them rest for 10 minutes while the grill heats up.
03 - 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.
04 - Grill the mushrooms for 3 to 4 minutes per side until tender with distinct grill marks, basting occasionally with any remaining marinade.
05 - 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.
06 - Remove from heat, sprinkle with fresh chopped parsley, and adjust seasoning with salt and pepper to taste. Serve warm with lemon wedges on the side.