Blend raspberries, sugar, and lemon juice until smooth.
Strain through fine mesh strainer to remove seeds.
Set aside 3 tablespoons puree for mousse.
In large bowl, add cold heavy cream, powdered sugar, and vanilla.
Beat with electric mixer until stiff peaks form (3 to 4 minutes).
Mix 3 tablespoons raspberry puree with sweetened condensed milk.
Gently fold raspberry mixture into whipped cream with spatula.
Mix just until combined. Do not overmix.
Spoon or pipe mousse into 6 serving glasses.
Cover with plastic wrap.
Refrigerate at least 3 hours or overnight.
Top with fresh raspberries, whipped cream, mint, or chocolate shavings.
Serve chilled.