Preheat the oven to 400°F (200°C).
Trim the leaves and stem of the cauliflower, keeping the core intact.
Slice the cauliflower into 1-inch thick 'steaks.'
Drizzle the steaks with olive oil and sprinkle with paprika, garlic powder, salt, and pepper.
Place the steaks on a lined baking sheet and roast for 25-30 minutes, flipping halfway through, until golden and tender.
In a blender or food processor, combine the roasted red pepper, garlic, pistachios, tomato paste, red wine vinegar, smoked paprika, and a pinch of salt.
While blending, slowly drizzle in the olive oil until the sauce is smooth and creamy. Adjust salt and pepper to taste.
Spread a generous layer of romesco sauce on a serving plate.
Place the roasted cauliflower steaks on top of the sauce.
Optional: Garnish with fresh parsley or toasted nuts for extra crunch.
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