01 - Combine chopped dates and 2 tbsp water in a small saucepan. Cook over low heat for 3-4 minutes, stirring constantly until soft and jammy. Remove from heat and let cool completely to room temperature.
02 - In a large chilled bowl, whip cold heavy cream using an electric mixer or whisk until soft peaks form. Refrigerate immediately to maintain structure.
03 - Whisk egg yolks with granulated sugar in a separate bowl until pale and thickened, approximately 3-4 minutes. Stir in orange blossom water and lemon zest until fully incorporated.
04 - Process cooled date mixture in a food processor or blender until completely smooth. Gently fold date paste into egg yolk mixture until uniform in color and texture.
05 - Fold whipped cream into date-yolk mixture in two separate additions, using a spatula with gentle lifting motions to preserve airiness until smooth and fully incorporated.
06 - In a completely clean bowl, whisk egg whites to stiff peaks. Carefully fold into mousse base using gentle folding motions, maintaining maximum volume.
07 - Divide mousse evenly among individual serving glasses or bowls, smoothing tops with a spatula.
08 - Refrigerate for minimum 2 hours until completely set and firm to the touch.
09 - Sprinkle chopped pistachios and finely grated orange zest over each portion. Add sliced dates if desired. Serve chilled.