Soak the raisins and rosemary leaves in a small bowl of lukewarm water. Set aside
Preheat the oven to 180C (350F) and grease a 9” pie pan with one tablespoon olive oil (or non-stick cooking spray). Set aside.
In a large bowl, combine the chestnut flour, water, maple syrup, and remaining olive oil with a fork. Continue stirring until a smooth batter forms. If the batter is too thick, add another tablespoon or two of water to thin slightly.
Drain the raisins and rosemary leaves and pat dry. Add half of the raisins, walnuts, and pine nuts to the batter and stir to combine.
Pour the batter into the pie pan and spread with a spatula to form a smooth, uniform layer. Evenly distribute the rosemary and remaining raisins, walnuts, and pine nuts on top of the batter.
Place pan on the middle shelf of the pre-heated oven and bake for 30-35 minutes or until the top is dried and starting to crack.
Remove from oven and cool slightly before cutting into thin slices and serving.