3 Tbs. extra-virgin olive oil
3 large cloves garlic, peeled
1 Tbs. coriander seeds
1-1/2 tsp. fennel seeds
1-1/2 tsp. dried sage
1 small (5-1/2- to 6-lb.) Hubbard squash, halved lengthwise and seeded
2 Tbs. unsalted butter
1 large leek (white and light-green parts only), halved lengthwise and thinly sliced crosswise
2 medium carrots, peeled and cut into small dice
Kosher salt
5 cups lower-salt chicken or vegetable broth
1 bay leaf
2 tsp. fresh lemon juice
Freshly ground black pepper
1/2 cup hazelnuts, toasted, skinned, and chopped
2 Tbs. thinly sliced chives
Several small pinches Espelette pepper or cayenne