Preheat oven to 325F. Line 16 muffin wells in a muffin tray with paper liners.
Sift the 1/4 cup superfine sugar, flour, cornstarch, and salt into a bowl. Repeat this twice (so dry ingredients are sifted together 3 times in total). Don't skip this part!
3/4 cup superfine sugar, 7 tbsp all-purpose flour, 1 tbsp cornstarch, 1/8 tsp table salt
Add egg whites, warm water, and cream of tartar to a large bowl and beat until foamy. Slowly add remaining 1/2 cup superfine sugar, and beat until egg whites hold soft peaks. Beat in vanilla.
3/4 cup freshly separated egg whites*, 1 tbsp warm water, 3/4 tsp cream of tartar, 1-1/4 tsp vanilla extract
Use a rubber spatula to fold dry ingredients into the egg whites 1/3 at a time, being careful not to deflate the egg whites.
Fill muffin wells about 3/4 full. Bake until cupcakes are light golden in color, and a toothpick inserted in the center comes out clean, about 18 to 25 minutes, rotating the muffin tray once halfway through.
Cool cupcakes for 5 minutes in the pan and then carefully transfer them to a wire rack to finish cooling completely.
For the whipped cream topping, Add all ingredients to a large bowl and beat until the cream holds stiff peaks.
1-1/2 cups heavy whipped cream, 1/4 cup confectioners' sugar, 1/2 tsp vanilla extract
When cupcakes are completely cool, you can frost them. Simply spoon the whipped cream decoratively on top, or use a piping bag to pipe it on. Add fresh berries to the top of each cupcake.
fresh berries for topping