Preheat your oven to 400 degrees F. Line a rimmed baking sheet with foil and generously spray it with olive oil.
Remove the cabbage’s damaged outer leaves. Cut it in half, then into wedges as shown in the video. Leave the core in - there's no need to cut it out, and if you do, the wedges will fall apart.
Rinse the cabbage wedges, then carefully dry them using paper towels.
Place the wedges in a single layer on the prepared baking sheet. Generously spray their tops with olive oil. Season with kosher salt, garlic powder, and red pepper flakes.
Roast the cabbage wedges until golden brown and fork-tender, 25-30 minutes. Serve immediately.
To prep the cabbage, remove the outer leaves, cut the cabbage into wedges, and rinse them under running water. This will help get rid of any insects hiding inside the cabbage. Be sure to dry the wedges before baking them.