Remove the outer leaves from the cauliflower. Slice the cauliflower from top to stem into thick “steaks,” about 1 to 1½ inches each. You should get 2–3 solid steaks and some loose florets (you can roast those too).
Place the steaks in a steamer basket over simmering water. Steam for 7–9 minutes until just tender but not falling apart. Remove carefully and let them cool slightly.
Whisk together water, lemon juice, tahini, maple syrup, balsamic, nutritional yeast, smoked paprika, garlic powder, onion powder, turmeric, black pepper, paprika and sea salt if using. The mixture should be pourable, add a splash of water if needed.
Place the cauliflower steaks on a baking sheet lined with parchment. Brush or spoon the marinade generously over both sides. Let them sit for 10–15 minutes to soak up the flavor.
Preheat oven to 425°F. Roast the steaks for 20–25 minutes, flipping halfway through, until edges are golden and lightly crisp.
Top with fresh parsley, lemon zest or a drizzle of balsamic glaze. Serve over quinoa, greens, mashed potatoes or rice.