Make the cake doughnuts:

1. In a large bowl, whisk together the dry ingredients (flour through salt on the list). Make a well in the center.
2. In another bowl whisk together the remaining ingredients, except oil. Pour into the center of the dry ingredients and mix until just combined. Do not over mix! Cover with plastic wrap and refrigerate for one hour or overnight.
3. Remove the dough and roll onto a well-floured surface, about 1/2 to 3/4 inch thick. Use a cookie cutter or something round to cut circles into the dough. To cut out the center, you can use a frosting tip or a bottle cap, or whatever else you have around.
4. Fill a large saucepan with about 3 inches of oil until it is 360 to 365 degrees. Fry the doughnuts 2-3 at a time, about three minutes, flipping halfway. They should be puffed and golden brown. Using a thermometer is very important, as the temperature must be in the right range! Remove with slotted spoon and cool on a paper towel.

Make the chocolate glaze:

1. Microwave or heat the butter, vanilla, corn syrup, milk, and dark chocolate and whisk until smooth. Whisk in the powdered sugar
2. Spoon over or dunk donuts in the chocolate glaze. Cover with sprinkles if desired.