In a small bowl, whisk together oil, salt, pepper, garlic powder, red pepper flakes, Dijon mustard, and sun-dried tomatoes.
Brush all sides of cabbage wedges with oil mixture. Place wedges on a large baking sheet. Cover wedges with foil and roast 45 minutes, remove foil and roast an additional 10 minutes or until golden and fork-tender. If desired, garnish with chopped cilantro. Serve immediately.