Preheat the oven and prepare the pumpkin. Heat your oven to 400°F (200°C) and line a large baking sheet with parchment paper. Rinse the squash well, then carefully cut it in half from top to bottom with a sharp, sturdy knife. Scoop out the seeds. Use a large spoon to remove the soft pulp and seeds. Save the seeds, because they make a crunchy roasted snack.
Slice into wedges. Cut each half into wedges about 1 inch (2.5 cm) thick, so they roast evenly. Oil the wedges. Place the wedges on the lined sheet, drizzle with 2 tablespoon (30 ml) of olive oil, and toss gently until every piece is lightly coated. Drizzling olive oil over raw red kuri squash wedges on a baking sheet.
Add the red onion (optional). Tuck the onion slices between the pumpkin pieces, so they do not touch the squash too much. This keeps the pumpkin plain and neutral, which matters if you plan to reuse the leftovers in sweet recipes.
Roast and serve. Bake for 45 minutes at 400°F (200°C). The squash is done when it is fork-tender and golden at the edges. Let the wedges cool for a couple of minutes, then serve warm.
