If you prefer to cook these indoors, you can use a griddle pan on the stove top to char the beetroots all over then finish them off in a hot oven (200°C) until they are tender and cooked through.
First make the dukkah: Put a dry frying pan on a medium heat and add the nuts and coriander seeds. Roast for about 5 minutes until golden-brown. Stir occasionally to ensure they do not burn. Take off the heat.
Place in a food processor and add the cumin, chilli, oregano and salt. Run a few blitzes or pulses – it should be in small pieces but not too finely chopped. Store in a dry, airtight container.
To prepare the beetroot: Add charcoal or firewood to half of the barbecue so that you have space to roast the beetroot using indirect heat later.
Light the barbecue and once it is burning strongly, place the beetroots straight onto the charcoal so that the outer layer burns.
Turn several times using tongs. Pick up the beetroots, place on the grill and position them on the charcoal-free side. Close the lid and roast using indirect heat for around 1 hour until the beetroots feel soft when you gently press the skin. You can measure the core temperature – it should preferably be above 85°C.
Peel the beetroots once they are cool enough to handle without burning yourself. It can be
a little tricky to remove the skin – try pulling it off with your fingers; otherwise, cut it off with a knife.
Let the barbecue get really hot so you can toast the bread. Butter the slices of bread then grill them quickly on the side without butter, turn them over onto the buttered side and grill until there are clear grill stripes.
Slice the beetroot and crumble some feta on top. Place them on the grill briefly so that thecheese begins to melt.
Place a few slices of beetroot with feta onto each slice of toast, sprinkle with Dukkah and top with herbs and sea salt flakes.
Adapted from The Green Barbecue Cookbook, Hardie Grant