Step 1: Preheat oven to 350°F (175°C) and grease an 8-inch round cake pan.
Step 2: In a large bowl, whisk together Nutella, eggs, milk, and vegetable oil until smooth.
Step 3: Add flour, baking powder, salt, and vanilla extract to the bowl, and mix until just combined.
Step 4: Pour batter into the prepared pan and smooth the top.
Step 5: Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Step 6: Let cake cool in pan for 10 minutes, then transfer to a wire rack to cool completely.
Step 7: Dust with powdered sugar before serving.