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 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. Refrigerate immediately to maintain structure.
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 until fully blended.
04 - Process cooled date mixture in a food processor or blender until smooth paste forms. Gently fold date paste into yolk mixture until completely incorporated.
05 - Fold refrigerated whipped cream into date-yolk base in two separate additions, using a spatula with gentle lifting motions to preserve air volume and maintain light texture.
06 - In a clean, grease-free bowl, whisk egg whites until stiff glossy peaks form. Carefully fold whites into mousse base using minimal strokes to retain maximum aeration.
07 - Divide mousse evenly among individual serving glasses or bowls. Tap containers lightly on counter to release any air bubbles and smooth surfaces.
08 - Refrigerate mousse for minimum 2 hours or until completely set and firm to the touch. Cover with plastic wrap if chilling longer than 3 hours to prevent skin formation.
09 - Top each portion with chopped pistachios, finely grated orange zest, and sliced fresh dates. Serve chilled alongside buttery shortbread or Lebanese semolina cookies.