For the croutons:
1/4 cup unsalted butter
2 teaspoons finely chopped garlic
2 teaspoons finely chopped fresh thyme
6 cups day-old bread, crust removed, cubed
6 tablespoons finely grated Parmesan, plus more for garnish
Salt and freshly ground black pepper

For the salad:
1 small red onion, sliced thinly lengthwise
3 tablespoons sherry vinegar
Gray salt
4 cups peeled, seeded, and diced butternut squash (1/2-inch dice)
1/2 cup plus 1 1/2 tablespoons extra-virgin olive oil
1 tablespoon chopped fresh sage
Freshly ground black pepper
1/2 pound Brussels sprouts, ends trimmed, then quartered
1/2 cup fresh Italian parsley leaves