Begin by peeling the mangoes and cutting them into small, bite-sized cubes, aiming for a total of about 4 cups. Set aside in a bowl while you prepare the cream mixture.

In a large, chilled mixing bowl, pour in the heavy cream. Using a hand mixer on medium speed, whip the cream for 3-5 minutes or until it thickens and forms stiff peaks.

Gradually add the sweetened condensed milk to the whipped cream, folding it in gently with a spatula until smooth.

In a rectangular dish, lay down a layer of Biscoff cookies. Spread a third of the whipped cream mixture over the cookies, followed by a layer of chopped mangoes. Repeat layering twice more.

For the final layer, arrange the leftover Biscoff cookies on top and spread the remaining whipped cream mixture evenly. Cover with plastic wrap and refrigerate for at least 4 hours.

Once chilled, garnish with additional sliced mangoes and crushed Biscoff cookies before serving.