Place the egg whites into a spotlessly clean bowl. Whisk on a medium speed of your mixer until foamy, then add the cream of tartar. Continue to whisk until soft peaks form. Add the superfine sugar, a little at a time. Continue to whisk until all the sugar has been incorporated and the egg whites are very stiff and shiny.
using two spoons or a piping bag, place rounded spoonfuls of the egg white mixture in rows on the lined baking tray. You want them to be around 2-1/2 inches in diameter.
Place in the oven, them immediately reduce the oven temperature to 275 and bake for 1 hour.
Turn the heat off and leave the meringues undisturbed in the oven until the oven is completely cold (or, better yet, overnight) to allow the meringues to dry out.
Cut the strawberries into quarters. Place about 1/3 of the raspberries and the confectioner's sugar into a blender or food processor and process until just pureed (or you can mash them with a potato masher or fork).
Place the remaining berries to the side and pour over the orange liqueur. Set aside to macerate while you whip the cream (the longer you let the berries steep, the better).
Whip the cream until soft peaks form and set aside. Whip the marscapone and fold into the heavy cream.
Break up the meringues (if desired. you can also just use the meringues as a base to cover with berries and top with cream/marscapone mixture and drizzle with berry sauce (which could also have a raspberry liqueur or syrup added to it) into bite-sized pieces and add them to the whipped cream. Add the chopped strawberries and gently add blueberries and raspberries, reserving a few for garnish.
gently fold in all but a few tablespoons of the puree, marbling it through the cream mixture.
Spoon into individual serving dishes or goblets and drizzle with the remaining puree and reserved berries.