Serves 6 to 8
1 small cauliflower, outer leaves removed, broken into small florets (about 450g)
1 medium red onion, peeled
5 tablespoons olive oil
1/2 teaspoon finely chopped rosemary
7 large eggs
1/2 cup basil leaves, chopped
90g green banana flour, sifted
1 1/2 teaspoon baking powder
1/3 teaspoon ground turmeric
150 g coarsely grated Parmesan or another aged cheese
Melted unsalted butter, for brushing
2 tablespoons black sesame seeds
Salt and black pepper
Preheat the oven to 200°C.
Steam cauliflower florets until quite soft. They should break when pressed with a spoon. Set aside in a colander to cool.
Cut 4 round slices, each 5-mm thick, off one end of the onion and set aside. Coarsely chop the rest of the onion and place in a small pan with the oil and rosemary. Cook for 10 minutes over medium heat, stirring from time to time, until soft. Remove from the heat and set aside to cool. Transfer the onion to a large bowl, add the eggs and basil, whisk well, and then add the flour, baking powder, turmeric, Parmesan, 1 teaspoon salt, and plenty of pepper. Whisk until smooth before adding the cauliflower and stirring gently, trying not to break up the florets.
Line the base and sides of a 24-cm springform cake pan with parchment paper. Brush the sides with melted butter, then the sesame seeds and toss them around the inside of the pan so that they stick to the sides. Pour the cauliflower mixture into the pan, spreading it evenly, and arrange the reserved onion rings on top. Place in the center of the oven and bake for 45 minutes, until golden brown and set; a knife inserted into the center of the cake should come out clean. Remove from the oven and leave for at least 20 minutes before serving. It needs to be served just warm, rather than hot, or at room temperature.