01 - Preheat oven to 425°F. Line a large baking sheet with parchment paper.
02 - Remove damaged outer cabbage leaves. Cut cabbage into 1-inch thick slices, keeping the core intact.
03 - Place cabbage steaks in a single layer on the lined baking sheet.
04 - Combine olive oil, garlic powder, smoked paprika, dried thyme, sea salt, and black pepper in a small bowl.
05 - Brush both sides of each cabbage slice generously with the seasoned oil mixture.
06 - Roast for 25 to 30 minutes, flipping once halfway through, until edges are golden and centers are tender.
07 - Remove from oven. Garnish with chopped parsley and a squeeze of lemon juice if desired. Serve hot.