In a medium bowl whisk together all-purpose flour, cake flour, cornstarch, baking soda, baking powder, and salt.
In a separate large bowl whisk together melted butter, brown sugar, and granulated sugar until smooth.
Add the Biscoff spread and mix until fully combined. Add the egg, egg yolk, and vanilla extract and mix until smooth and glossy.
Add the dry ingredients into the wet ingredients and mix until just combined.
Fold in the white chocolate chips and crushed Biscoff cookies.
Scoop large dough balls about 5–6 oz each. Flatten dough in your hand and place a white chocolate Lindt Truffle in the center. Wrap dough around the filling and seal completely.
Roll into tall dough balls rather than flattening.
Place assembled cookies onto a parchment-lined baking sheet and refrigerate for 45–60 minutes.
Preheat oven to 375°F. Bake cookies for 12–14 minutes or until edges are set and centers are slightly underbaked. Let cookies cool on the baking sheet for 10 minutes before transferring to a cooling rack.