Line an 8x8-inch square baking dish with parchment paper, leaving an overhang on the sides for easy removal.

In double boiler melt the sweetened condensed milk and white chocolate chips over medium low heat. Alternatively you can use a microwave-safe bowl, and microwave in 30-second intervals, stirring well after each, until the mixture is smooth and fully melted. 

Remove from heat and stir in the Biscoff spread until completely smooth. Then add in most of the crushed cookies and mix, leaving some to add over the top of the fudge.

Pour the fudge mixture into the prepared baking dish, spreading it evenly with a spatula.

Sprinkle the remaining crushed Biscoff cookies evenly over the top, pressing them gently into the fudge. If desired, drizzle additional Biscoff spread over the surface for extra flavor and decoration.

Place the pan in the refrigerator and chill for at least 2 hours, or until the fudge is firm.

Remove the fudge from the pan using the parchment overhang. Slice into 16 squares or your desired size.