1. Score the chestnuts
Cut each chestnut crosswise on the top with a sharp knife.

2. Roast and peel the outer shell
Place the chestnuts in a hot, dry pan and roast them until the cuts open and the outer shells start to peel away.

3. Boil 
Transfer the roasted chestnuts into cold water, then bring the water to a boil. Let them cook for about 20–30 minutes. You can add baking soda to the water to help the skin come off.

4. Remove the inner skin
Take the chestnuts out one by one and peel off the inner layer while they’re still warm. A spoon can help with this step. Don’t worry if some break or if a few bits of the soft inner skin remain — they’ll be blended later anyway!

5. Infuse with clove aroma
Crush about 3 cloves in a mortar. Toast them briefly in a hot pan until they release their fragrance.

6. Lightly roast the chestnuts
Add the peeled chestnuts to the same pan and roast them for a couple of minutes to bring out their full flavor.

7. Blend into a smooth purée
Transfer the roasted chestnuts to a food processor and blend until smooth. You can add a little water to help with blending — just remember, the more water you add, the longer you’ll need to cook the purée later to reduce it.

8. Make the sugar syrup
In a pan, combine sugar, salt, and vanilla with the water. Heat until the syrup reaches at least 105°C and forms large bubbles.

9. Combine syrup and purée
Add the chestnut purée to the hot syrup and whisk gently to combine (careful the sugar syrup is very hot). Continue cooking and stirring until the mixture thickens and if you make traces with your whisk or a spoon, the traces remain.

10. Fill into jars
Place a wet kitchen towel on your counter. Spoon the hot chestnut mixture into sterilized jars, then turn them upside down and let them cool.