Prep: trim the leaves and the end of the core from the cauliflower
Preheat the oven to 450°F.
Cut the cauliflower in half, from top to bottom. Cut each half from top to bottom in half-inch cross sections, resulting in a mixed bag of whole cauliflower “steaks” and flat florets. This is one of the very few cases where it’s okay to cut a vegetable into different sizes because with width will be more or less the same whether you have a whole “steak” or smaller pieces.
Transfer the cauliflower to a baking sheet large enough to comfortably accommodate all the pieces with a little space to spare, or use two baking sheets, or cook in two batches.
In a small bowl or measuring cup, combine the olive oil, turmeric, salt and pepper. Use a fork or whisk to combine well. Drizzle the spiced olive oil over the cauliflower. Use your best tools (your clean hands) to coat the florets, covering them completely.
Place the baking sheet(s) in the center of the oven and roast for 20 to 30 minutes, rotating the baking sheet halfway through to ensure even browning. The cauliflower should be a beautiful yellow color from the turmeric and nicely browned on the edges from the caramelization.