01 - 
                In a small saucepan, combine fresh raspberries and granulated sugar. Cook over medium heat for 5-7 minutes, stirring occasionally, until the raspberries break down. Strain the mixture through a fine mesh sieve to remove seeds, leaving a smooth puree. Add lemon juice if desired. Let the puree cool completely.
              
              
              
                02 - 
                If using gelatin, dissolve 1 tsp gelatin powder in 2 tbsp cold water. Let it bloom for 5 minutes, then microwave for 5-10 seconds until melted. Cool slightly, then stir into the raspberry puree.
              
              
              
                03 - 
                In a large bowl, combine chilled heavy whipping cream, powdered sugar, and vanilla extract. Whip with an electric mixer until stiff peaks form. Be careful not to over-whip.
              
              
              
                04 - 
                Gently fold the raspberry puree into the whipped cream in thirds until fully combined. The mixture should be light pink and airy.
              
              
              
                05 - 
                Spoon or pipe the mousse into serving glasses or bowls. Refrigerate for at least 2 hours to set and allow the flavors to meld.