Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius/gas mark six). Line and grease an eight and 1/2-inch (22-centimeter) springform pan. Set aside.

In a saucepan of simmering water, cook cauliflower about 15 minutes, or until florets are soft. Drain and set aside.

In a frying pan, heat the oil and sauté onions and garlic about five minutes. Remove and set aside.

Transfer cauliflower, onions, and garlic to a large bowl. Add cherry tomatoes, basil, mozzarella balls, and mixed herbs and mix well.

In a mixer, whisk together eggs, flour, baking powder, salt, and pepper.

Pour egg mixture into the large bowl and transfer to the prepared pan.

Bake 10 minutes and then remove from the oven briefly.

Add plum tomatoes, positioning them in a circular pattern starting from the outside.

Return pan to the oven for 35 minutes more, or until golden and set. A knife inserted in the center will come out clean.

Leave to cool about 20 minutes before removing from the pan.

Garnish with sprigs of fresh basil and a dusting of black pepper.