In a stand mixer fitted with the paddle attachment, beat the butter and both sugars together until light and creamy.

Add the cookie butter and vanilla, mixing until smooth. Add the eggs, one at time, and continue mixing until ingredients are incorporated.

Add the flour, cornstarch, baking soda, cinnamon, and salt. Mix until combined. Stir in 1 cup of the white chocolate chips and half of the Biscoff cookies. Cover, and refrigerate dough for at least two hours, or up to three days.

Preheat the oven to 350ºF and line a baking sheet with parchment paper. Roll the dough into balls about the size of a golf ball, then place them on the baking sheet about 2 inches apart. Flatten each dough ball slightly so that it resembles a little hockey puck.

Bake for 8-11 minutes, or until the edges are set and the centers are puffy but still look slightly underdone. Immediately after removing cookies from the oven, press extra white chocolate chips and Biscoff pieces into the cookies.

Allow cookies to cool on the baking sheet for 10 minutes before transferring to a wire rack to cool completely.