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 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. It can be a roasted look, but not burnt, that makes the harissa bitter. Pierce the cauliflower with a knife to check if it's done.
Brown the vegetarian balls according to the instructions on the package.
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.