Heat oven to 250°F. LIne a large baking sheet with parchment paper.
In a large squeaky clean glass or metal bowl (or the bowl of your stand mixer) beat egg whites w until very frothy and white. Gradually add sugar, ¼ cup at a time and beat until very stiff and glossy. Add the cream of tartar and cornstarch. The meringue should be very stiff and the tip should not move or bend over.
Spread the meringue on parchment paper-lined baking sheet, about 2 inches thick (or form into 3-inch meringue circles, if you like. Reduce the oven temperature to 225°F. and bake for 90 minutes. Turn the oven off and let the meringue sit in the oven for an hour or even overnight.
In a medium bowl, combine sliced strawberries with Triple Sec or other orange liqueur and orange zest.
When ready to serve the dessert, whip the cream with the confectioner's sugar and vanilla just until stiff. Roughly crumble the meringue, leaving bite-sized pieces.* See note. Layer the crumbled meringue, strawberries and whipped cream, repeating layers to fill your dessert dishes. Garnish with a light dusting of orange zest.
* You may not need to use all the meringue. It is very sweet, so use your judgment as to how much you'd like to add to this dessert.If you don't have berry sugar, grind granulated sugar in a blender. It is much finer and dissolves more easily than granulated sugar.The meringue can be several days in advance. After it has completely cooled, wrap tightly and store in a cool place.