In a small saucepan, combine fresh raspberries and granulated sugar over medium heat. Stir gently for 5–7 minutes until the raspberries soften and release their juices. Once heated, remove from the heat and let cool slightly. Transfer the mixture to a blender or food processor and puree until smooth, then strain it through a fine-mesh sieve to remove the seeds for a silky Raspberry Mousse base.

In a small bowl, sprinkle unflavored gelatin over cold water, allowing it to sit for 5 minutes to bloom. Afterward, heat the mixture in the microwave for about 10-15 seconds until the gelatin dissolves completely. Blend the gelatin mixture into the cooled raspberry puree, stirring until well incorporated.

Once the raspberry puree is ready with the gelatin incorporated, set it aside to cool fully. This is crucial to avoid melting the whipped cream later.

In a mixing bowl, use an electric mixer to whip the chilled heavy cream on medium speed until soft peaks form (about 3–5 minutes). Gradually add powdered sugar and vanilla extract, continuing to whip until stiff peaks form.

Gently fold one-third of the raspberry puree into the whipped cream using a spatula. Carefully add the remaining puree in two more additions, folding gently to maintain the airy texture.

Spoon the blended mousse mixture into individual serving glasses or bowls, covering with plastic wrap or lids, and refrigerate. Chill for at least 2 hours, or until set.

Once set, garnish each mousse with a few fresh raspberries on top before serving.