Pre-heat oven to 350 degrees and prep cupcake pan with paper liners - 24.
With mixer, beat egg whites till frothy. Gradually add in just 1/2 cup of the sugar, beat until whites have stiff peaks.
In a large bowl, whisk together flour, 1 cup of sugar, baking soda, salt, and cocoa powder. Make a well in the center and pour in oil and some milk, mix well, add remaining milk and yolks and mix till smooth.
Fold in egg whites into chocolate batter. Pour into cupcake pan.
Bake for 15 minutes, depending on your oven. You can do the toothpick test. If the toothpick comes out clean it is done.
Cool and let rest on a wire rack.
FROSTING: In a sauce pan, combine water, sugar, salt and butter. Bring to a boil. In a small bowl, mix together 1/2 cup water and cornstarch to form a smooth liquid. Once sauce pan mixture starts to boil, add cocoa carefully, then slowly pour in cornstarch mixture. This process should happen quickly and the frosting will seize up. Let frosting cool. Make a little hole in the cupcake and fill and frost cupcakes.