This recipe is just 2 ingredients and it produces a rich, decadent, individual-sized, flourless Nutella cake. While most desserts taste best warm and straight out of the oven, this is one recipe where you must give the cake several hours to settle so that the flavors can fully develop. If you try to eat the cake right away, it will likely taste a little eggy. If you're in a hurry, I created a recipe that adds one more ingredient, but you won't have to wait several hours. Check out my 3-Ingredient Flourless Nutella Mug Cake. I also have a 4-Ingredient Nutella Mug Cake or 3-Ingredient Nutella Brownie, which don't require much wait time.
Break egg into an oversized microwave-safe mug and whisk. Even though the final cake will not be that tall, it will rise quite a bit while cooking, so make sure you use a mug to cook it in. The finished cake will pull away from the sides so you can easily remove and plate it or put in a small ramekin.
Add Nutella and whisk vigorously until the batter is smooth and the egg is fully incorporated. Because the mixture is so dark, it will be hard to see if egg streaks remain. Lift your whisk a couple times to make sure you don’t see evidence of unmixed egg still in the batter.
Cook in microwave for about 1 minute. Cake will look the slightest bit gooey on top, but as long as the cake has risen and is set, it should be ready. Let cake sit for several hours (I recommend 2-3) before eating, so the chocolate hazelnut flavor can fully develop and overcome any eggy taste.
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.