Begin by placing fresh raspberries into a blender, and blend them until smooth and velvety for about 1-2 minutes. Then, strain the puree through a fine-mesh sieve into a bowl to remove the seeds, using a spatula to press the mixture gently.

In a medium saucepan, combine the raspberry puree, granulated sugar, and freshly squeezed lemon juice over low to medium heat. Stir the mixture gently until the sugar dissolves completely, which should take about 3-4 minutes.

While your raspberry mixture is warming, in a small bowl, sprinkle unflavored gelatin over cold water. Allow it to sit undisturbed for 5 minutes to bloom, then whisk it into the warm raspberry mixture until fully dissolved.

In a large mixing bowl, pour the cold heavy whipping cream and drizzle in some vanilla extract. Using an electric mixer, whip the cream on medium speed until soft peaks form, approximately 3-5 minutes.

Gently fold the cooled raspberry mixture into the whipped cream using a spatula, ensuring not to overmix.

Spoon the raspberry mousse mixture into your selected serving glasses or bowls, filling them about three-quarters full. Cover with plastic wrap and place in the refrigerator.

When ready to serve, remove from the fridge and garnish each serving with a few fresh raspberries and a sprig of mint.