Preheat your oven to 425°F (220°C). Line one or two large sheet pans with parchment paper or lightly grease with oil. If using convection, reduce to 400°F.

Remove any wilted or damaged outer leaves from the cabbage. Place the head core-side down on a cutting board. Using a large, sharp chef's knife, slice the cabbage into rounds approximately ¾ to 1 inch thick. You should get 4–6 steaks depending on the size of the head. Reserve any loose outer leaves and roast them alongside as chips.

Arrange the cabbage steaks in a single layer on the prepared sheet pan(s), making sure they are not touching. Use two pans if needed to avoid crowding.

In a small bowl, whisk together the olive oil, smoked paprika, garlic powder, salt, black pepper, and red pepper flakes (if using). Brush this mixture generously over the top surface of each cabbage steak, coating all the way to the edges.

Carefully flip each steak and brush the remaining oil mixture over the second side as well.

Roast in the preheated oven for 15 minutes, until the bottom side is deeply golden and beginning to char slightly at the thinnest edges.

Using a wide, sturdy spatula, carefully flip each steak. Return to the oven and roast for an additional 12–15 minutes, until the second side is golden and the center of each steak is fork-tender.

Remove from the oven and let rest on the pan for 2 minutes. Transfer to a serving platter, garnish generously with fresh parsley, and serve immediately with lemon wedges for squeezing.