Line a baking sheet with parchment paper. Drop 8 dollops (1/2 tbsp each) of cookie butter (from the 1/4 cup) on it, then freeze for 15-20 minutes.

Preheat the oven to 350°F. Line a large baking sheet and set aside.

In a large bowl, cream together the butter, cookie butter, brown sugar, and granulated sugar. Add the egg and vanilla extract, and mix again.

Mix in the flour, cornstarch, baking soda, and salt.

Scoop large cookie dough balls (1/4 cup each), make a well in the center, and stuff each one with a frozen cookie butter dollop. Fold the dough over to seal, then place on the prepared baking sheet and bake for 10 minutes.

Allow the cookies to cool down. Drizzle with melted cookie butter and sprinkle with Biscoff cookie crumbs.