This Broccoli Grilled Cheese Sandwich is hearty, filling, and quite possibly the most elevated grilled cheese sandwich recipe you’ve ever tasted. Imagine crispy, crunchy roasted broccoli paired with creamy, nutmeg-dusted butternut squash, sweet caramelized onions kissed with balsamic vinegar, and melty Swiss cheese - all nestled between buttery, toasted artisan bread.