Preheat oven to 350 F. Coat the doughnut (or muffin) tins with PAM or similar cooking spray.
In a large bowl, add nutella, eggs, and flour. Mix to combine.
Fill each doughnut cavity with the mixture - all the way to the top.
Bake for about 12-15 minutes (or until toothpick comes out clean)
Let cool.
Meanwhile, add the 1/2 cup Nutella for frosting to a microwavable bowl. Heat for 30 seconds at a time, stirring in between, until it is more runny. You want it to flow off a spoon slowly.
Once brownie doughnuts have cooled mostly, carefully remove them from the pan, and dip the tops directly into the melted nutella. Sprinkle with your desired toppings, or just keep them as is.
Enjoy!