Preheat oven to 350°F. Line or grease mini cupcake/muffin pan.
Put the Nutella and egg in a medium bowl and whisk until smooth and well blended. Add the flour and whisk until blended.
Spoon the batter into the prepared muffin tins (about 3/4 full) and sprinkle with the chopped chocolate.
Bake about 10 minutes. Set on a rack to cool completely.
Notes
Recipe adapted and found on Savory Sweet Life, who reprinted it from Abby Dodge, cookbook author of Desserts 4 Today: Flavorful Desserts with Just Four Ingredients
The nutrition information provided are only estimates based on an online nutritional calculator. This is not a comprehensive list of all the nutrients in the recipe (i.e., does not include vitamins, cholesterol, etc). I am not a certified nutritionist. Please consult a nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have.