Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper.
Trim the stem ends of the cabbage heads, then cut each cabbage into 1-inch thick slices, creating "steaks". Place the cabbage steaks on the prepared baking sheet.
Whisk together the olive oil, salt, black pepper, garlic powder, and onion powder, and brush the mixture onto both sides of each cabbage steak to coat.
Roast the cabbage steaks for 25 minutes or until tender and slightly golden brown.
Remove the steaks from the oven, drizzle with lemon juice, and garnish with parsley.
Notes
To store: Transfer cabbage steaks to an airtight container and refrigerate for 3-4 days. When you're ready to enjoy them again, reheat in the oven at 350°F, in the air fryer, or in the microwave.