01 - Combine chopped dates and 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 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 volume.
03 - Whisk egg yolks with granulated sugar in a separate bowl until mixture turns pale and thick, approximately 3-4 minutes. Stir in orange blossom water and lemon zest until fully incorporated.
04 - Puree cooled date mixture in a food processor or blender until completely smooth. Fold date paste into the egg yolk mixture until uniformly combined.
05 - Gently fold the chilled whipped cream into the date-yolk base in two separate additions. Use a spatula with light, lifting motions to maintain the airy texture.
06 - In a clean, grease-free bowl, whisk egg whites until stiff glossy peaks form. Carefully fold into the mousse base using gentle folding motions to preserve maximum air volume.
07 - Spoon or pipe the finished mousse into individual serving glasses, ramekins, or decorative bowls. Fill containers nearly to the top, leaving minimal space for garnish.
08 - Refrigerate for at least 2 hours until mousse is completely set and holds its shape. For best results, chill overnight to develop full flavor intensity.
09 - Just before serving, sprinkle chopped pistachios over the surface. Top with freshly grated orange zest and arrange sliced dates attractively on top.