01 - Combine chopped dates and 2 tbsp water in a small saucepan. Cook over low heat for 3-4 minutes, stirring constantly until dates soften into a jammy consistency. Remove from heat and allow to cool completely to room temperature.
02 - Pour cold heavy cream into a large bowl. Using an electric mixer or whisk, whip until soft peaks form. Transfer to refrigerator to maintain structure until needed.
03 - Whisk egg yolks and granulated sugar in a separate bowl until mixture becomes pale and thickened, approximately 3-4 minutes. Incorporate orange blossom water and lemon zest, mixing until fully blended.
04 - Process cooled date mixture in a food processor or blender until smooth paste forms. Gently fold date paste into egg yolk mixture until uniformly incorporated.
05 - Fold chilled whipped cream into date-yolk base in two separate additions. Use gentle folding motions to maintain airiness while achieving smooth consistency.
06 - Beat egg whites in a clean bowl until stiff peaks form. Carefully fold whipped whites into mousse base using minimal strokes to preserve maximum volume and air structure.
07 - Distribute mousse evenly among individual serving glasses or bowls. Refrigerate for minimum 2 hours or until completely set and firm.
08 - Sprinkle chopped pistachios and grated orange zest over each portion. Add sliced dates if desired. Serve chilled.