Castagnaccio: Tuscan Chestnut Flour Cake

Make traditional Tuscan Castagnaccio, a rustic chestnut flour cake with raisins, rosemary, and nuts. A simple, earthy dessert.

Castagnaccio is a traditional rustic Tuscan chestnut flour cake that is usually served in the fall and winter months following the annual chestnut harvest. This cake has a deep, rich, earthy flavour that is quite unlike typical cakes and desserts found elsewhere.

More authentic versions of this recipe do not include any form of sweetener. Instead, they rely on the addition of dried fruit to sweeten the cake.

I have added a little honey to this recipe to appeal more to an American palate. Even so, you may find Castagnaccio is a bit of an acquired taste if you prefer more sugary treats.

If you are looking for more delicious uses for chestnut flour, check out my recipe for Tuscan Chestnut Crepes with Ricotta & Honey. 

Tips for Best Results

• Sift the Chestnut Flour – Chestnut flour can clump easily. Sifting ensures a smooth, lump-free batter and a lighter texture in the finished cake. If you don’t have a sifter, use a fine-mesh strainer.
• Soak the Raisins and Rosemary – Let them sit in lukewarm water before adding to the batter. This rehydrates the fruit, releases flavor, and prevents dry spots in the cake.
• Measure Liquids Carefully – Chestnut flour absorbs liquid differently than wheat flour. Start with the recommended water amount, but add a little more if the batter seems too thick.
• Mix Gently – Stir the batter just until smooth. Overmixing can make the cake dense or tough.
• Layer Evenly – Spread the batter uniformly in the pan and scatter the raisins, walnuts, pine nuts, and rosemary on top evenly to ensure each slice has balanced flavor and texture.
• Bake Until Cracked – The top should look dry and slightly cracked, but not burnt. This indicates the cake is cooked through.
• Cool Before Slicing – Allow the cake to cool slightly in the pan. This helps it firm up so slices hold together and prevents crumbling.
• Optional Sweetness Adjustments – Taste the batter before baking if using honey. Adjust to your preference, especially if using sweeter dried fruit.

Ingredients & Substitutions

• Chestnut Flour – The base of this cake. Can be substituted with a mix of chestnut and almond flour if you prefer a milder flavor.
• Raisins – Adds natural sweetness. Other dried fruit like chopped figs, currants, or chopped dates works well too.
• Rosemary Leaves – Provides the traditional earthy aroma. Thyme or a small pinch of sage can be used if desired.
• Honey (Optional) – Sweetens the cake slightly for an American palate. Maple syrup or agave syrup are suitable alternatives, or omit entirely for a more authentic rustic taste.
• Extra Virgin Olive Oil – Keeps the cake moist and adds depth of flavor. Neutral oils like avocado or light olive oil can be used instead.
• Walnuts – Adds crunch and nutty flavor. Pecans or hazelnuts are good alternatives.
• Pine Nuts – Adds texture and a subtle, buttery taste. Sunflower seeds or slivered almonds can be used as a substitute.
• Water – Used to form the batter. You can also use unsweetened plant-based milk for a slightly richer flavor.

Looking for More Tuscan Recipes?

Check out more of my favourite Tuscan favourites!

These Tuscan Chestnut Crepes with Ricotta & Honey, known as Necci, are a popular Tuscan dessert typically filled with a combination of fresh sheep’s milk ricotta cheese and honey.

This Tuscan Ragù (Tuscan-Style Meat Sauce) is an authentic Italian ragù recipe. Serve over pasta, gnocchi, or polenta for a hearty meal.

This Tuscan pork chop recipe is inspired by the flavors of Tuscany; thick pan-seared pork chops with sweet roasted grapes and earthy fennel.

Castagnaccio: Tuscan Chestnut Flour Cake

Yields: 8-10 Servings | Prep time: 15 minutes | Cook time: 30-35 minutes

Ingredients

• 1/3 cup raisins, divided
• 2 tablespoons fresh rosemary leaves
• 3 cups chestnut flour, sifted
• 1 2/3 cups lukewarm water
• 2 tablespoons honey*
• 2 tablespoons extra virgin olive oil
• ¼ cup chopped walnuts, divided
• ¼ cup pine nuts, divided

*Honey is optional. Use more or less honey depending on level of sweetness desired. 

Directions

1. Soak raisins and rosemary leaves in a small bowl of lukewarm water. Set aside.
2. Position oven rack to center position. Preheat oven to 350°F and grease a 9” pie pan with olive oil or non-stick cooking spray. Set aside.
3. In a large bowl, combine chestnut flour, water, honey, and olive oil with a fork. Continue stirring until a smooth batter forms. If batter is too thick, add another tablespoon or two of water to thin slightly.
4. Drain raisins and rosemary leaves and pat dry. Add half of the raisins, walnuts, and pine nuts to batter and stir to combine. 
5. Pour batter into prepared pie pan and spread with a spatula to form a smooth, uniform layer. Evenly distribute rosemary and remaining raisins, walnuts, and pine nuts on top of batter.
6. Place pan in pre-heated oven and bake for 30-35 minutes or until the top is dried and starting to crack.
7. Remove from oven and cool slightly before cutting into thin slices and serving. Enjoy!

Note: For best results, sift the chestnut flour before using. If you don’t have a flour sifter, add chestnut flour to a small fine mesh strainer and gently shake over the mixing bowl to remove any clumps.