Peel and prepare the mangoes by slicing some thinly for decoration and cutting the rest into small cubes, ensuring they are ready for layering.

Add the chilled heavy cream to a large bowl and whisk on medium speed until it thickens to a soft, ribbony consistency without reaching stiff peaks.

Pour in the sweetened condensed milk and continue whisking until the mixture forms stiff peaks, being careful not to overmix.

Prepare your pan by lining it with parchment paper if you plan to lift the dessert out later, or leave it unlined if serving directly from the pan.

Arrange a layer of Biscoff cookies at the bottom, then spread a portion of the whipped cream evenly over them and top generously with mango pieces.

Repeat the layering process with another layer of cookies, cream, and mangoes, keeping the layers even for a consistent texture.

Finish with a final layer of cookies and the remaining cream, then decorate the top with mango slices and crushed cookies for added texture.

Cover the pan tightly with cling wrap and refrigerate overnight until fully set and easy to slice.

Slice into portions and serve chilled for the best texture and flavor.