In a large mixing bowl, whisk the heavy cream and sugar until soft peaks form.
Gently fold in the sweetened condensed milk and vanilla extract. Beat again until thick and smooth.
In a saucepan over medium heat, cook the raspberries, 2 tbsp sugar, and lemon juice for about 10 minutes, mashing and stirring until a thick jam forms. Let cool.
Fold the raspberry jam into the cream mixture, swirling to create red streaks.
Pour mixture into a loaf pan. Fold in fresh blueberries and top with extra berries in the shape of a flag.
Freeze for at least 12 hours before serving.