Finely crush 3 of the sandwich cookies into crumbs and roughly chop the remaining 7 into chunks. Place the chunks in the freezer while you make the base.
Whisk the mascarpone, powdered allulose, almond milk, vanilla extract and salt until completely smooth, then stir in the fine cookie crumbs for that classic speckled look.
Whip the heavy cream to stiff peaks in a large bowl.
Fold the whipped cream into the mascarpone mixture in two additions, keeping it light and airy.
Gently fold in most of the chilled cookie chunks, then spread the mixture into a loaf pan and press the remaining chunks on top.
Cover and freeze for at least 6 hours, until firm. Rest for 10 minutes at room temperature before scooping.