Onion, Apple and Cheese Gratin – Fustini's Oils & Vinegars

Ingredients

• 3 large onions, chopped
• 2 medium Granny Smith apples, cored and chopped
• 2 tablespoons Fustini's Garlic olive oil, plus more for greasing
• 1/2 teaspoon dried thyme
• salt to taste
• 1/4 teaspoon crushed red pepper
• black pepper to taste
• 1 cup torn crusty bread
• 1/2 cup shredded Gruyere cheese, divided
• 1/2 teaspoon dried sage, crushed
• 1/4 cup heavy cream
• splash of Fustini's Michigan Apple balsamic (optional)