An incredibly simple, one-bowl recipe that's perfectly rich and so easy to make!
Preheat oven to 350°F/180°C. Grease an 8×8-inch pan.
In a large mixing bowl whisk together eggs and sugar for about 1 minute until well combined. Add Nutella, oil, milk, vanilla, and salt. Whisk until smooth.
Add the flour, cocoa powder, baking powder, and baking soda and whisk until well combined and smooth. Stir in the coffee or water, then fold in the chocolate chips with a rubber spatula.