Preheat your oven to 350°F (175°C). Crush digestive biscuits until they resemble fine crumbs and mix with melted butter. Press into the bottom of a square ring mold and bake for about 10 minutes until slightly golden.

In a blender, combine frozen raspberries and sugar. Blend until smooth and strain through a sieve to remove seeds. Set aside.

Beat cream cheese until smooth. Gradually add raspberry puree, lemon juice, and lemon zest, mixing until fully combined.

Whip heavy cream until stiff peaks form and gently fold into the cream cheese mixture. Pour over the crust and spread evenly.

Cover and refrigerate for at least 4 hours or overnight to set.

Once set, remove from mold, slice, and serve chilled, optionally garnished with fresh raspberries.