Grate or finely chop the garlic. Add the garlic to the mushrooms. Place a large pot on medium-high heat. Add 4-5 tablespoons single varietal olive oil. Add mushrooms and garlic. Stir for about 1 minute. Add the red wine. Increase the heat to high, stir and cook for 1 minute. Add 18 year traditional balsamic and stir through. Season with salt and pepper, if desired. Reduce heat to low and simmer 10 minutes. Stir in 1/4 teaspoon butter olive oil. Allow to cool. Drain and serve (reserve the liquid). Can store remaining mushrooms in marinade in refrigerator.