In a medium saucepan, combine fresh raspberries, sugar, and lemon juice. Cook over medium heat for around 5-7 minutes, gently stirring until the raspberries break down and release their juices.

Use a fine-mesh strainer over a bowl. Pour the cooked raspberry mixture into the strainer, pressing gently to extract all the juice and pulp while leaving the seeds behind.

In a small bowl, sprinkle the gelatin over cold water and let it sit for about 5 minutes until it thickens.

Gently reheat the raspberry puree over low heat until warm but not boiling. Add bloomed gelatin and stir until completely dissolved.

In a large mixing bowl, whip the heavy cream, powdered sugar, and vanilla extract together on medium speed until soft peaks form.

Gently fold the whipped cream into the cooled raspberry mixture using a spatula.

Spoon the raspberry mousse mixture into serving containers. Cover and refrigerate for at least 3-4 hours to set.

Garnish with fresh raspberries or mint leaves before serving.