Winter Squash Stock

Name: Winter Squash Stock
Ingredients: 3 lb. (1.4 kg) winter squash, such as butternut, delicata, or acorn, halved; 1⁄4 cup (60 ml) grapeseed oil, divided; 1⁄2 lb. (225 g) white onions, cut into small dice; 1 lb. (455 g) leeks, dark green parts removed, cut into small dice; 1 lb. (455 g) carrots, cut into small dice; 1⁄2 small fennel bulb, coarsely chopped, fronds removed; 1⁄2 head garlic, unpeeled; 2 sprigs thyme; 8 black peppercorns; 1 bay leaf; 4 sprigs flat-leaf parsley; Sea salt to taste