Place the remaining olive oil, lemon, water, garlic, herbs, hot red pepper flakes, black peppercorns, and salt in sauté pan. Simmer for 5 minutes. Pour over the mushrooms in the bowl. Stir in the optional balsamic vinegar. Let mushrooms cool in marinade. Cover and refrigerate overnight. Bring to room temperature before serving. To serve, lift out of marinade with a slotted spoon.