The first step, assemble all your ingredients next to your cooking area.
Prepare your chestnuts and pecans by chopping them into small pieces.
Next, pour water, corn syrup, and brown sugar into the saucepan.
Place the saucepan on the stove, stir the mixture and let it boil.
Lower the temperature to medium and let it simmer.
Remove the saucepan away from the stove.
Add a tablespoon of vanilla syrup to your mixture and stir.
Let it cool for a few minutes.
Sieve the mixture into a jar and store it away.
You can refrigerate your syrup to lengthen its shelf life.