Get ready. Fill a large pot with water about 3/4 of the way with water and bring to a boil over high heat. Line a large plate with paper towels and set near your stove. Position a rack in the middle of the oven and heat the oven to 400°F. Coat a large sheet pan or two with a thin layer of olive oil.
Parboil the cauliflower. When the water is boiling, salt generously and add the cauliflower wedges. Cook for about 5 to 7 minutes, or so just until the cauliflower begins to soften (it helps to add a plate on top of the cauliflower to keep it submerged in the water). Use tongs to transfer the cauliflower to the prepared plate to drain.
Make the garlic-harissa rub/sauce. To the bowl of a large food processor fitted with a blade, add the garlic cloves, parsley, cumin, harissa, tomato paste, lime juice, and a drizzle of olive oil (about 2 tablespoons). Season with salt and pepper (about 3/4 to 1 teaspoon each). Blend until you have a homogeneous thick mixture.
Coat the cauliflower with the garlic-harissa rub. Pat the cauliflower dry, then arrange the wedges on top of the oiled sheet pan. Now generously coat the wedges all over with the garlic-harissa mixture. (Make sure you cover all of the cauliflower, this is important for flavor.) Drizzle generously with olive oil.
Bake. Bake the cauliflower on the middle rack of the heated oven. Every 15 minutes or so, drizzle the cauliflower with more olive oil and/or baste with the pan juices. Do this until the cauliflower is charred in many parts (so important for flavor), about 45 minutes in total.
Finish and serve. Remove from the oven, garnish with a sprinkle of finely chopped parsley, and serve.
Notes
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