1. Preheat the oven to 400° and lightly grease a small baking sheet with vegetable oil. Set aside.
2. Trim the base of the cauliflower to remove any green leaves and the woody stem.
3. In a medium bowl, combine the yogurt with the lime zest and juice, chili powder, cumin, garlic powder, curry powder, salt and pepper.
4. Dunk the cauliflower into the bowl and use a brush or your hands to smear the marinade evenly over its surface. (Excess marinade can be stored in the refrigerator in an airtight container for up to three days and used with meat, fish or other veggies.)
5. Place the cauliflower on the prepared baking sheet and roast until the surface is dry and lightly browned, 30 to 40 minutes. The marinade will make a crust on the surface of the cauliflower.
6. Let the cauliflower cool for 10 minutes before cutting it into wedges and serving alongside a big green salad.