Add brown sugar, water, diced apples, and apple pie spice to a medium saucepan.
Bring to a boil stirring constantly until the sugar dissolves to make sure it doesn’t burn.
Lower the heat and simmer for 15 minutes stirring occasionally.
Take the syrup off the heat, stir in vanilla extract, and allow it to cool for 10-15 minutes. The longer it sits, the more apple flavor the syrup will have.
Strain the syrup into a large measuring cup or a bowl through a fine mesh strainer. Use a spoon to squeeze as much syrup out of the apples as possible.
Transfer to an airtight jar and store in the fridge for up to 2 weeks. Wait for the syrup to cool completely before closing with a lid.
