Step 1: Preheat your oven to 350°F (175°C) for even baking.
Step 2: Line your 9x13 inch baking pan with parchment paper, leaving some overhang.
Step 3: In a large mixing bowl, combine flour, brown sugar, baking powder, and salt. Stir until mixed. Add egg, melted butter, milk, and vanilla; mix until just combined.
Step 4: Press the crust mixture evenly into the bottom of the prepared pan.
Step 5: In another bowl, beat together cream cheese and Biscoff spread until smooth. Add eggs, melted butter, vanilla, and powdered sugar; mix until silky.
Step 6: Pour the filling over the crust and spread evenly.
Step 7: Bake for 30-35 minutes until edges are set and the center is slightly gooey.
Step 8: Cool in the pan for 20 minutes before lifting out with parchment and cooling completely before slicing.
