Bring a large pan (about 1/3 full) with water and some salt to the boil to cook the cauliflower. Remove the leaves from the cauliflower.
Carefully lower the whole cauliflower (stem side down) into the hot water, bring to the boil and cook for about 8 minutes. Be sure not to overcook the cauliflower. In the meantime, mix HALF the harissa with the yogurt. Carefully remove the cauliflower from the pan with a slotted spoon and let it drain well and cool.
Generously rub the cauliflower with the harissa/yogurt mixture and place it on a baking dish. Preheat the oven to 180℃ while you prepare the ingredients for the 'dukkah'.
Dukkah: crush the sesame seeds, coriander seeds, aniseed and fennel seeds using a mortar and pestle and mx it with the dried oregano. Bruise the nuts with the flat side of a chef's knife and roughly chop them. Roast them over medium heat in a frying pan and let them cool. Grind them a little finer in the mortar and mix it with the rest. You can add a little salt to the 'dukkah' to your own taste.
Place the cauliflower in the oven and let it roast until golden brown for 10 to 15 minutes. Check after 10 minutes, and increase the temperature if necessary. Take care not to burn the harissa. Pierce the cauliflower with a knife to check if it's tender in the centre.
Place the remaining half of the harissa paste into a large bowl with the mince and mix gently until combined. Oil your hands then taking small spoonfuls of mixture roll the mince into meatballs. Fry the meatballs in a small amount of oil in a large frying pan for 8-10 minutes over a moderate heat, turning frequently until piping hot throughout.
Divide some lettuce on the serving platter and place the cauliflower on top. Place the balls around it and garnish with pomegranate seeds, dukkah, beet greens and coriander.