Method
Prepare your fire. It needs to be a combination of hot embers and flaming wood.
Divide the clay into 8 pieces, each about the size of a small apple. Form each piece into a disc, about 2.5cm thick.
Place one clay disc on a board, set a few sage leaves in the middle with some salt, and then place a whole, unpeeled onion on top. Trickle with olive oil and season with more salt and black pepper. Take a second clay disc and place it on top of the onion. Then gather up the edges of the clay to envelop the onion completely. Seal the seams well. Repeat this process for all the onions.
Nestle the clay spheres around the glowing embers of your fire, but not directly in them. Cook for about 1½ hours, turning the spheres every 15–20 minutes so they bake evenly. Take your time with this one: if the onions cook too fast, at too high a heat, the clay may crack and the onions could burn. You’ll need to feed the fire during this time to maintain the heat.
Once the time is up, take the clay-wrapped onions out of the fire, using tongs or a tea towel. Use the back of a heavy cook’s knife or simply a stone to crack the clay open, and carefully lift the onions out onto a board. It’s worth doing just one first: it should be soft and tender inside.
Slice the onions in half and arrange them over a platter. Trickle with olive oil and sprinkle liberally with salt and pepper. Serve at once, with good bread, and perhaps some sausages.
