Eggplant, zucchini and yoghurt (upside down) cake
adapted from Yotam Ottolenghi's Aubergine, courgette and yoghurt upside-down cake
- 2 large zucchini, coarsely grated
- Salt and freshly ground black pepper
- 2 large eggplants, cut into 1.5cm-thick rounds
- 60ml olive oil, plus 2 tsp for brushing
- 1 large onion, peeled and finely chopped
- 1 large garlic clove, peeled and crushed
- 10g oregano leaves, roughly chopped
- 50g activated pistachio nuts
- 300g goat (or greek) yoghurt
- Finely grated zest of 1 lemon
- 50g cheddar cheese, grated
- 2 eggs, separated
- 50g green banana flour
Heat the oven to 220C. Line a 21cm cake tin with baking paper and brush with oil.
Mix the grated zucchini with half a teaspoon of salt and put in a colander over a bowl or in the sink for 20 minutes. Transfer the salted zucchini to the centre of a clean tea towel, draw up the sides, then squeeze out as much liquid as possible. Put the zucchini (you should have about 200g-worth) in a bowl and set aside.
In a large bowl, mix the eggplant slices with two tablespoons of oil, a quarter-teaspoon of salt and a good grind of pepper. Spread out on two oven trays lined with baking paper and roast for 30 minutes, until golden-brown. Set aside to cool, then arrange the aubergine in a spiral in the base of the cake tin, so the slices overlap and cover the base.
Turn down the oven to 180C. Heat two tablespoons of oil in a medium frying pan on a medium-high heat, then fry the onion for seven minutes, until soft and starting to turn golden-brown. Add the garlic and oregano, fry for a minute, until the the garlic is starting to brown, then add to the zucchini bowl. Add the pistachios, yoghurt, lemon zest, cheese, egg yolks, green banana flour, a quarter-teaspoon of salt and plenty of pepper, then mix to combine.
In a separate bowl, whisk the egg whites to soft peaks, then gently fold them into the zucchini mix until just combined, then spoon on top of the eggplant in the cake tin. Bake for 45 minutes, until the cake is golden-brown, then set aside to cool down a bit.
For an upside-down cake, release the cake from its tin and invert on to a plate, so the eggplants are now sitting on top. If you're clumsy and happy to have the eggplant at the bottom - do nothing.
Remove the baking paper, cut into individual portions and serve warm or at room temperature.