01 - Combine chopped dates and water in a small saucepan. Cook over low heat for 3-4 minutes, stirring constantly until dates soften into a jam-like consistency. Remove from heat and allow to cool completely to room temperature.
02 - In a chilled large bowl, whip cold heavy cream using an electric mixer or whisk until soft peaks form. Refrigerate immediately to maintain structure.
03 - Whisk egg yolks and granulated sugar in a separate bowl until mixture becomes pale and noticeably thickened. Incorporate orange blossom water and lemon zest, mixing until fully combined.
04 - Process cooled date mixture in a food processor or blender until completely smooth. Gently fold date paste into yolk mixture until uniform in color and texture.
05 - Fold chilled whipped cream into date-yolk mixture in two separate additions, using a spatula with gentle lifting motions to maintain airiness and prevent deflation.
06 - In a thoroughly clean bowl, whisk egg whites until stiff glossy peaks form. Carefully fold into mousse base using minimal strokes to preserve maximum volume.
07 - Distribute mousse evenly among individual serving glasses or bowls, tapping gently on counter to release any air pockets.
08 - Refrigerate for minimum 2 hours or until completely set and firm to the touch. Mousse should hold its shape when spoon is inserted.
09 - Sprinkle chopped pistachios and grated orange zest over surface immediately before serving. Add sliced dates as optional garnish for additional texture and visual appeal.