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 allow to 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. Place in refrigerator to maintain structure.
03 - Whisk egg yolks with granulated sugar in a separate bowl until mixture becomes pale and thickened. Incorporate orange blossom water and lemon zest until fully blended.
04 - Process cooled date mixture in a food processor or blender until achieving a smooth, uniform paste consistency. Fold thoroughly into egg yolk mixture until completely incorporated.
05 - Gently fold whipped cream into date-yolk base in two separate additions, using a spatula with lifting motions to maintain airy texture.
06 - Whisk egg whites in a clean bowl until stiff peaks form. Carefully fold into mousse base using delicate folding motions to preserve maximum air volume.
07 - Distribute mousse evenly among individual serving glasses or bowls using a spoon, smoothing tops with back of spoon.
08 - Refrigerate for minimum 2 hours until mousse achieves firm, set consistency.
09 - Top each serving with chopped pistachios, finely grated orange zest, and additional sliced dates. Serve immediately.