Preheat oven to 350° F. Boil 1 cup water in microwave. Whisk in cocoa and vinegar until smooth. Let cool.
Meanwhile, in a stand mixer, beat 1 stick butter for 4 to 5 minutes on high speed. Add the sugar and beat for another couple minutes. Add the oil and eggs, mixing well.
In a separate bowl, whisk together the flour, salt and baking soda. Add to the mixer and mix until just combined. Fill lined cupcake tins about 2/3 full.
Bake at 350°F for 12-15 minutes or until they spring back when lightly touched. Cool completely on wire racks
To make the frosting, beat the butter until smooth. Beat in 3 cups of powdered sugar until smooth. Add enough of the milk to reach the right consistency for spreading or piping. Beat in a pinch of salt to taste.
Frost the cupcakes, generously of course :) and top with sprinkles.