2 3/4 pounds orange-flesh winter squash, such as butternut
2 tablespoons olive oil
1 medium leek, trimmed, white and green parts, cut into 1/4-inch pieces (1 cup)
3 cloves garlic, peeled and minced
1 teaspoon finely grated fresh ginger, or more to taste
1 medium parsnip, (4 ounces), peeled and cut into 1/4-inch pieces
1 teaspoon salt, plus more to taste
1/4 teaspoon freshly ground black pepper, plus more to taste
4 cups Homemade Chicken Stock, or canned low-sodium chicken broth, skimmed of fat
2 three-quarter-inch slices whole-wheat bread, crusts removed
3 tablespoons freshly grated Parmesan cheese