Preheat oven to 350 F. Boil 1 cup water on stovetop or microwave. Whisk in cocoa and vinegar until smooth. Let cool.
Meanwhile, with a mixer, beat 1 stick butter for 5 minutes on high speed. Add the sugar and beat for another couple minutes. Add the oil and eggs, mixing well.
Separately, whisk together the flour, salt and baking soda.
Add to the previous mixture (sugar, eggs, oil, and butter) mix until combined thorougly.
Fill lined cupcake tins about 2/3 full.
Bake at 350 for 12-15 minutes or until they spring back when lightly touched. Cool completely on wire racks.
Frosting: Beat the butter until smooth.
Beat in 3 cups of powdered sugar on high for 1-2 minutes or until smooth and fluffy.
Beat in the caramel sauce, salt and 1 tablespoon of milk or cream. Add more if needed for a smooth frosting.
Frost the cupcakes and top with a caramel candies