Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper or a silicone baking mat.

1. In a large mixing bowl, beat together the softened butter and cookie butter until creamy and smooth, about 2-3 minutes.
2. Add the granulated sugar, egg, and vanilla extract, and mix until fully incorporated.
3. In a separate bowl, whisk together the all-purpose flour, baking soda, salt, and ground cinnamon.
4. Gradually add the dry ingredients to the wet mixture, mixing until just combined. Add 2 tablespoons of milk to adjust dough consistency if necessary. The dough should be thick but pliable.
5. Fold in the white chocolate chips if using, ensuring they’re evenly distributed throughout the dough.
6. Scoop about 2 tablespoons of dough, roll into a ball, and place on the baking sheet, spacing them 2 inches apart. Flatten the dough balls slightly with a spoon or your fingers.
7. Bake for 8-10 minutes, or until the edges are golden and the centers are soft. Be careful not to overbake.
8. Allow the cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.
9. For the topping, melt 2 tablespoons of cookie butter in the microwave for 20-30 seconds or until smooth. Drizzle over the cooled cookies, and optionally sprinkle with crushed speculoos cookies.
10. Serve and enjoy your delicious cookie butter cookies!