Rinse all the berries and plums. Hull and quarter the strawberries, and slice the plums into ¼ inch thick pieces. Set aside.

Mix the Liquids:

In a large pitcher, combine the rosé wine, pomegranate juice, freshly squeezed lemon juice, superfine sugar, Grand Marnier, and Cognac or brandy. Stir well until the sugar is completely dissolved.

Add Fruits and Chill:

Add the prepared strawberries, raspberries, and plums to the pitcher. Stir gently to mix the fruits with the liquid. Cover and refrigerate for at least 2 hours, preferably overnight, to allow the flavors to meld.

Serve:

Just before serving, add a generous amount of ice to the pitcher to chill. Pour the sangria into glasses filled with extra ice. Make sure some fruit pieces get into each glass.

Garnish (Optional):

Garnish with a sprig of mint or a lemon slice for an extra touch of summer.