Use a damp cloth to thoroughly wipe the mushroom caps, removing any dirt and excess moisture. Pat dry with a clean towel.
In a small bowl, whisk together olive oil, minced garlic, and balsamic vinegar to create a marinade.
Lay the mushrooms stem-side down and brush both sides generously with the marinade using a brush, ensuring they are well coated.
Preheat the grill to medium-high heat until hot and lightly oiled to prevent sticking.
Place the mushrooms on the grill, gill-side down first, and listen for the sizzle as they start to cook. Grill for about 4-5 minutes until they develop grill marks and begin to darken.
Flip the mushrooms to the stem side and continue grilling for another 4-5 minutes, basting with remaining marinade if desired. The caps should turn glossy and darken further, releasing a smoky aroma.
Check for tenderness by gently pressing the caps; they should feel tender yet still hold their shape. Remove from the grill once done.
If using, sprinkle fresh herbs over the hot mushrooms for an added burst of freshness and flavor.
Serve the grilled mushrooms hot, allowing the juices and smoky aroma to shine. Enjoy as a hearty main or flavorful side.
