Rinse the raisins under running water and soak them in cold water to rehydrate.

Sift the chestnut flour into a large bowl, add the water, and mix with a whisk by hand. Once you have a smooth, even batter, add the pine nuts, reserving a small amount to sprinkle on top before baking.

After 10 minutes, drain and dry the raisins, then add them to the batter, setting aside a small amount. Mix the batter well and add the salt.

Grease a 12-inch (32 cm) round cake pan with olive oil and pour in the batter, spreading it evenly.

Evenly sprinkle the reserved pine nuts and raisins over the top of the batter.

Drizzle the olive oil over the top and, if you like, add rosemary needles. Bake at 385°F (195°C) for about 35 minutes.

When the surface cracks and the nuts are golden, remove from the oven and let cool before serving.