Cut the broccoli heads along the side, to create a flat surface. Reserve the o-cuts, then cut the broccoli into ‘steaks’ about 2 cm (¾ inch) thick; you should get at least 2–3 steaks out of each broccoli. Drizzle some olive oil onto a tray, add the steaks and toss to coat. Set aside.
Preheat the oven to 190°C (375°F). Line a baking tray with baking paper. While the oven is preheating, pop the plums for the tkemali on the baking tray, give them a drizzle of olive oil, then whack them into the oven. Pull them out after about 15 minutes, when they’re blistered and softened, and are leaching out ruby red liquid; this should be roughly around the same time the oven is at‑temperature.
For a shortcut: Oil the broccoli well and cook in a 220°C (425°F) oven until they start to burnish. Bonus points for leaving the baking tray in the oven to heat up, so that the florets really cop the heat as soon as they hit.
Pop the plums and the remaining tkemali ingredients in a blender and blitz to a purée. Taste for seasoning and‑acid, adding extra vinegar if need be.
Meanwhile, heat an ovenproof chargrill pan for at least 5–10 minutes, until searing hot. Working in batches, chargrill the oiled broccoli for 2–3 minutes, or until slightly charred. Transfer to a baking tray and repeat with the remaining broccoli, then transfer to the oven and bake for 15–20‑minutes, or until a knife can go through the thickest part of the broccoli stalks.
To serve, spoon the tkemali sauce around a platter, then arrange the broccoli on top. Drizzle with a little more olive oil. Sprinkle with salt flakes, freshly cracked black pepper and the walnuts. Serve warm, or at room temperature.
