Place the whole onions, skins and all, directly onto the coals. Roast, turning every 3–5 minutes, until tender when pierced with a knife, 20–30 minutes. Remove the onions from the coals and keep warm on a grill grate near the fire.

Gently blister the whole peppers on a grill grate over the fire, turning occasionally. Transfer peppers to a cutting board and remove the stems and seeds. Mince the peppers and add them to a small fire-safe pot with the ¼ cup extra virgin olive oil, the espelette pepper and a pinch of salt. Place near the fire and allow the peppers and olive oil to simmer while preparing the cucumbers.

Cut the cucumbers and lemons in half lengthwise. Transfer to a bowl, drizzle lightly with extra virgin olive oil and a pinch of salt and toss to coat evenly. Place the cucumbers and lemons cut side down on the grill rack above hot coals. Remove the lemons and cucumbers once they have developed dark caramelization on the cut side.

Trim the bottom end of the onions. Cut the onions into quarters and separate the layers, discarding the charred exterior. Transfer to a large bowl. Cut the cucumbers into 1- to 2-inch pieces and add to the bowl with the onions. Squeeze the juice of the grilled lemons into the bowl and toss with an additional drizzle of extra virgin olive oil.

To serve, spread the labneh across a large serving platter. Spoon the dressed onions and cucumbers over the labneh, then spoon the pepper mixture over the top. Finish with fresh torn mint. Serves 6–8.