In a saucepan, combine the raspberries, sugar, and lemon juice. Cook over medium heat, stirring occasionally, until the raspberries break down and the mixture slightly thickens. Allow it to cool, then strain to remove seeds, if desired.

Place the chopped white chocolate in a microwave-safe bowl and melt in the microwave for about 60 seconds, stirring every 20 seconds until smooth. Set aside to cool slightly.

In a mixing bowl, whip the heavy cream, vanilla extract, and sugar until stiff peaks form.

Gently fold the melted white chocolate into the whipped cream until fully incorporated.

Spoon a layer of raspberry sauce into the bottom of each serving glass.

Carefully spoon or pipe the white chocolate mousse over the raspberry layer, filling the glasses. For taller glasses, repeat the layers if desired.

Refrigerate the assembled mousse for at least 30 minutes to set.

Before serving, optionally garnish each glass with fresh raspberries and white chocolate shavings.