Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a medium bowl, whisk together all-purpose flour, baking soda, and salt.

In a large bowl, cream together unsalted butter, light brown sugar, and granulated sugar until fluffy. Add in egg and vanilla extract, mixing until smooth.

Gradually incorporate the dry mixture into the wet mixture until just combined.

Scoop about 1 tablespoon of dough, add Biscoff spread in the center, and seal with another tablespoon of dough.

Arrange cookie pies on the baking sheet, leave space for expansion, and bake for 12 to 14 minutes.

Remove from oven and let cool for about 5 minutes before transferring to a wire rack.