In a medium bowl, combine ¼ cup of balsamic vinegar, 2 tablespoons of soy sauce, and 3 minced garlic cloves. Stir in 1 teaspoon of dried thyme, and season with salt and pepper to taste. Whisk until well-blended.

Clean and slice your mushrooms to ¼ inch thickness. Marinate in the mixture for at least 30 minutes.

Thread marinated mushrooms onto skewers, leaving space between pieces.

Preheat your grill to medium-high heat, around 400°F (200°C).

Grill skewers for 2-3 minutes on each side until tender and marked.

Remove skewers from grill, let rest for a minute, and serve warm.