Preheat the oven to 190 C.
Fry the onions, garlic and rosemary in a non-stick pan using cooking spray. Add small splashes of water to the pan if needed to prevent sticking.
Mix the flour, baking powder, eggs, turmeric, fresh herbs, and 1 tsp salt together in a bowl. Add enough yoghurt / milk to make the mixture the consistency of a runny batter. If in doubt, make it slightly thinner rather than slightly thicker – you don’t want the end result dry.
Add the cooked onion and steamed cauliflower to the batter and mix to combine.
Transfer to a prepared baking dish of choice. A round dish works well. I line the dish with tinfoil or baking paper to make removing the cake easier.
Top with Parmesan cheese, sesame and nigella seeds, and then the reserved onion rings.
Bake for approximately 45 minutes, until a knife inserted in the center comes out clean. For a cheat version, you could bake it in the microwave for about 10 minutes if you are short on time.
Let the cake stand for about 20 minutes before serving with a fresh salad. Enjoy!