In a medium saucepan, combine the sugar, evaporated milk, butter, and egg.
Cook over medium heat until the mixture starts to lightly bubble. Stir CONSTANTLY!! or you will end up with scrambled eggs in your frosting!!
Remove from heat immediately and stir in remaining ingredients.
Cool to room temperature, then refrigerate while you prepare, bake, and cool cupcakes.
Preheat oven to 350 F.
Sift together flour, salt, baking soda, and cocoa powder into a separate medium-sized bowl. Use a fork or a whisk to ensure that the ingredients are mixed well after sifting. Set aside.
In a medium-sized mixing bowl or the bowl of a stand mixer, mix butter and sugar until fully combined. The end result should look like wet sand.
Melt the chocolate in the microwave or in a double boiler.
Once the melted chocolate is cool enough to touch, add it to the butter/sugar mixture and mix until just combined.
Mix in eggs and egg yolks one at a time until just combined.
Mix in oil, vanilla, and sour cream until just combined.
Add dry ingredients to wet ingredients in three additions, mixing until just combined after each addition.
Mix in water until just combined.
Fill cupcake liners 2/3 full and put in the oven.
Check for doneness at 18 minutes - a toothpick inserted into the center of a cupcake should come out clean. If they are not done, check again every three minutes until they are done.
Immediately remove cupcakes from the cupcake tin and place on a cooling rack or on the counter to cool to room temperature.
Cut out a cone in the center of each cupcake going almost all of the way to the bottom. Go ahead and eat the removed cones. You won't be needing them!
Fill the holes with German chocolate frosting using a spoon, scoop, or piping bag. They can mound over the top of the hole just a little bit.
Chocolate Buttercream Instructions
In the bowl of a stand mixer, beat butter at high speed for three minutes until light and fluffy.
Mix in cocoa powder.
Mix in powdered sugar a little bit at a time.
Mix in vanilla and salt.
Pipe over filled cupcakes.
Optionally, decorate with pecans, coconut, and chocolate syrup.
Always make the German chocolate frosting first. That way it has time to chill and thicken while the cupcakes are baking.You may have a little extra German chocolate frosting. If you do, it's wonderful to spread on toast or mix into ice cream.These cupcakes should be stored in an airtight container and will stay good for three days at room temperature or five days in a refrigerator.