Melt butter in the microwave for 20-30 seconds. In a separate bowl, combine brown sugar and white sugar. Pour melted butter over the sugar. Use a handheld mixer on medium speed to beat the butter and sugar until smooth. Make sure to get any remaining chunks of sugar well ground up.
Add cookie butter spread and beat until smooth.
Next, add flour and a pinch of salt. Beat for 30 seconds; dough will start to thicken.
Lastly, add milk and vanilla and beat until well combined.
To prepare the dip, combine softened cream cheese and Biscoff and beat until smooth.
Add powdered sugar and pure vanilla extract and mix with a spatula until combined.
Spoon the cookie dough into the dip so that there will be chunks of cookie dough throughout.
Serve with crackers, cookies or fruit. Keep chilled and remove from fridge at least 30 minutes before serving to allow it to soften.