Cream the room temperature butter, white sugar, and brown sugar in the bowl of a stand mixer or a mixing bowl with an electric mixer until light and fluffy.

Add the eggs and vanilla extract to the sugar/butter mixture and beat again. Scrape down the sides of the bowl if necessary.

In a separate bowl, sift or whisk together the all-purpose flour, milk powder, cornstarch, baking soda, and salt. Then add the dry ingredients to the the wet ingredients and mix together.

Crush the Biscoff cookies into course crumbs and add them and the white chocolate chips to the cookie dough. Stir together until combined.

Once the dough is mixed use a two-tablespoon cookie scoop to measure the dough and form a ball. Make an indent in the middle of the cookie dough ball and add about ½ - 1 teaspoon of Biscoff cookie butter spread. Fold the cookie dough around the cookie butter, making sure to pinch the dough so that none of the cookie butter is exposed.

Place the cookie dough balls on a baking sheet and refrigerate them for 30 minutes.

Space the cookie dough balls on a parchment-lined baking sheet about 2 inches apart and bake the cookies at 375 degrees for 8-10 minutes. Remove and allow the cookies to rest on the baking sheet for 5 minutes, then transfer the baked cookies to a cooling rack.