Preheat oven to 350 degrees Fahrenheit (177 degrees Celsius). Line one muffin or cupcake pan with liners, and set aside.
Place sugar in a food processor for about 2 minutes until it becomes fine, almost powder-like. Sift half of the sugar with the salt and cake flour, set aside remaining sugar.
In a large bowl, whisk together egg whites, water, cream of tartar, and vanilla. After whisking for approximately 2 minutes, switch to a hand or stand mixer. Gradually sift in the remaining sugar, beating at medium speed until medium peaks have formed.
Add the flour mixture a little at a time (you'll want to add it in about 8 additions). It should be just enough flour to dust the top of the peaks. Use a spatula to fold in the dry ingredients in a circular motion, being careful to not deflate the peaks.
Once all of the flour has been folded in, carefully spoon the mixture into the prepared pan, filling ¾ of the way full. Place in the oven and bake for 18-20 minutes or until the tops are lightly golden brown (they will also look a bit bubbly). Remove from the oven and allow to cool in the pan for 5 minutes before transferring to a wire rack to cool completely.
To make the whipped cream, combine all ingredients in the bowl of a stand mixer fitted with a whisk attachment. Slowly bring the speed up to high, and beat until the cream has reached the desired consistency. Pipe or spread onto cooled cupcakes.
Notes
Recipe Source: Adapted from Alton Brown, Angel Food Cake-Cupcakes are best served the same day they are baked.-Pipe chilled whipped cream on top of the cupcakes right before serving.STORE Angel food cupcakes in an airtight container at room temperature and will stay fresh for up to three days. You can FREEZE them for up to one month; however, freeze without the whipped cream topping. For best results, wrap each cupcake individually in plastic wrap before placing it in a freezer-safe bag.