01 - Preheat the oven to 425°F. Line a large baking sheet with parchment paper.
02 - Remove the outer leaves and trim the stem of each cauliflower, leaving the core intact.
03 - Place each head stem-side down and slice into 3/4-inch thick steaks. Expect 2-3 large steaks per cauliflower, plus florets from the ends.
04 - Arrange steaks and any loose florets in a single layer on the prepared baking sheet.
05 - In a small bowl, whisk together olive oil, garlic powder, smoked paprika, black pepper, and salt.
06 - Brush both sides of the cauliflower steaks with the seasoned oil mixture.
07 - Roast for 15 minutes until edges begin to brown.
08 - Carefully flip each steak, then roast for another 12-15 minutes, until golden brown and tender.
09 - Transfer to a platter. Drizzle with lemon juice, sprinkle with parsley and pine nuts if desired. Serve warm.