Roast the cauliflower: Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper.
Place the cauliflower on the prepared baking sheet.
In a small bowl, whisk together the avocado oil, smoked paprika, garlic powder, coriander, cumin, and salt. Using your hands or a silicone brush, rub the oil mixture all over the exterior of the cauliflower. Transfer to the oven and roast until the cauliflower is fork-tender but not falling apart, 50 to 55 minutes.
Meanwhile, make the green olive dressing: (It’s ideal to make the dressing right after you have popped the cauli- flower in the oven, so the flavors have time to meld.) In a small food processor, combine the olives, parsley, shallot, and garlic. Pulse until finely chopped. Scrape the mixture into a small bowl.
Whisk the lemon juice, olive oil, salt, pepper, and chili flakes into the olive mixture. The flavor of the shallot will mellow as the dressing sits until ready to use. Taste before serving; if you need to balance out an overly strong shallot, just add a pinch of sugar.
Remove the roasted cauliflower from the oven and let rest on the baking sheet for 5 minutes. Serve the cauliflower whole or cut into wedges on a medium platter, drizzled with the green olive dressing. Store leftovers in an airtight container in the fridge for up to 3 days.