Position a rack in the bottom third of the oven and preheat to 400°F.
In a large bowl, toss the squash with ¼ cup olive oil, 2 tablespoons apple cider vinegar, five-spice powder, salt, and pepper until evenly coated.
Arrange the squash wedges cut-side down on a large rimmed baking sheet, leaving space between the pieces.
Roast for 25 to 30 minutes, flipping halfway through, until the squash is tender when pierced with a knife and caramelized around the edges.
Transfer the squash to a serving platter. In a small bowl, whisk together the hot honey, remaining 1 tablespoon apple cider vinegar, 2 tablespoons olive oil, and garlic.
Drizzle the hot honey mixture over the warm squash. Scatter thyme leaves over the top and finish with flaky salt.
Notes
No need to peel: Kabocha squash has tender skin that softens as it roasts, so you can leave it on. It helps the wedges hold their shape and saves you a step.Cut it carefully: Kabocha squash is dense and can be tricky to cut. If the squash is especially hard, microwave it for 1 to 2 minutes to soften it slightly before slicing.Leave some space: Spread the wedges out on the baking sheet with room between them. Crowding the pan traps steam and prevents caramelized edges.Roast cut-side down: Placing the squash cut-side down against the hot pan gives you the best browning.Use hot honey to taste: If you prefer a milder kick, start with a lighter drizzle and add more at the table.Fresh thyme works best: Thyme adds an earthy note that balances the sweet and spicy glaze. Fresh rosemary is another good option.Make it ahead: Roast the squash up to a day in advance and refrigerate it. Reheat in a 400°F oven until warmed through, then add the hot honey mixture just before serving.