Preheat the oven to 200°C (400F). Line a baking sheet with parchment paper.
Cut the cauliflower into 4 slices, about 2cm thick, and place them on the baking sheet.
In a small bowl, mix together the olive oil, salt, pepper, paprika and garlic powder.
Brush the cauliflower steaks with the oil mixture on both sides.
Roast the cauliflower steaks in the oven for 15 minutes, then flip them over and roast them for another 10 minutes or so until tender and golden brown.
Air fryer method: put one or two cauliflower steaks in the basket, set it to “roast” for 15-20 minutes. Turn them over half-way through.