Castagnaccio (Tuscan Chestnut Cake)

Castagnaccio is one of those ancient Italian recipes that sounds unusual but tastes absolutely wonderful - a flat, dense cake made from chestnut flour, studded with pine nuts and raisins, and perfumed with rosemary. It's not sweet in the way you'd expect a cake to be: the sweetness comes entirely from the chestnut flour itself, which has a rich, nutty depth that's completely unique. This is proper Tuscan autumn food, traditionally baked in a wood-fired oven after the bread was done. The surface should crack as it bakes - that's how you know it's right.

Ingredients

• 300g chestnut flour, sifted (available from Italian delis or online)
• 400ml water
• 3 tbsp extra virgin olive oil (plus more for the pan)
• A generous pinch of fine salt
• 50g pine nuts
• 50g raisins, soaked in warm water for 15 minutes then drained
• Fresh rosemary leaves (about 2 sprigs' worth)

Method

1. Soak the raisins in warm water for 15 minutes to plump them up. Drain well.
2. Sift the chestnut flour into a large bowl (it clumps easily, so this step matters). Add the salt.
3. Gradually pour in the water, whisking constantly to prevent lumps. Add the olive oil and whisk until you have a smooth, pourable batter - about the consistency of thick cream.
4. Fold in most of the pine nuts and drained raisins, keeping some back for the top.
5. Oil a shallow 25cm round baking dish or cast-iron skillet generously. Pour in the batter - it should be about 2cm deep. Too thick and the centre won't cook; too thin and it dries out.
6. Scatter the reserved pine nuts, raisins, and rosemary leaves over the surface.
7. Bake in your pizza oven at 200-220°C for about 40 minutes, turning the dish occasionally for even baking. The castagnaccio is done when the surface is cracked and golden and a skewer comes out clean.
8. Let it cool to room temperature before serving - it's better warm than hot. Traditionally served with ricotta or a glass of new wine.