Standard filo pastry is fine but I hunted around Melbourne’s Prahran Market and found beautiful home-made filo.
Preheat oven to 180C.
Wash the spinach well and roughly chop it, retaining the stems.
Place 50 ml olive oil in a wide heavy-based pan, then add the onion and garlic. Cook for 2 minutes on a medium heat, then add the capers and half the spinach. Cook for 4 or 5 minutes until the spinach is wilted, then tip everything into a colander to drain. Press out as much liquid as you can, using a spoon, or your hands.
Pour the rest of the oil into the pan. Add the herbs and the rest of the spinach. Again, cook it over a medium heat for 4 or 5 minutes until the spinach is wilted, then tip the mixture into a colander to drain, pressing out as much liquid as you can.
Turn all the spinach mixture onto a board and chop it quite finely. Return to a bowl, add the eggs, ricotta and crumbled fetta and stir them in well. Adjust seasoning.
Melt the butter, then use some of it to grease a 35cm round tin. Lay a filo sheet on the bench. Brush it with butter, and repeat 4 times, so you have 5 sheets of layered buttered pastry. Place a third of the spinach mix along the length of the pastry, then roll it into a sausage shape. Gently form the sausage into a spiral shape and lay it in the centre of the tin.
Repeat the process of layering pastry with the second and third portion of spinach mixture, adding these sausage shapes to continue the spiral outwards and fill the tin. Brush the top of the pastry with butter and sprinkle with the ground fennel and a little pepper.
Bake until golden brown for 30 to 40 minutes. Cool a little and remove from tin to serve, cutting or pulling apart as the mood takes you.