Slow-Cooker Mushrooms in Savory Sauce

Ingredients

• 2 pounds medium fresh mushrooms
• 1 package (14.4 ounces) frozen pearl onions, thawed
• 4 garlic cloves, minced
• 2 cups reduced-sodium beef broth
• 1/2 cup dry red wine
• 3 tablespoons balsamic vinegar
• 3 tablespoons olive oil
• 1 teaspoon salt
• 1 teaspoon dried basil
• 1/2 teaspoon dried thyme
• 1/2 teaspoon pepper
• 1/4 teaspoon crushed red pepper flakes