Follow these simple steps to create your very own batch of Mocha Hazelnut Brownies:

1. Preheat your oven to 350°F (175°C) and grease a 9×9-inch baking pan.
2. In a bowl, mix the hazelnut spread and melted butter until smooth.
3. Add brown sugar, eggs, and vanilla to the mixture. Stir until combined.
4. In another bowl, whisk together flour, cocoa powder, baking powder, and salt.
5. Gradually add the dry ingredients to the wet mixture, then mix in the cooled coffee until just combined.
6. Fold in the chopped hazelnuts if using.
7. Pour the batter into the prepared pan and spread evenly.
8. Bake for 20-25 minutes or until a toothpick inserted into the center comes out with a few moist crumbs.
9. Let the brownies cool before cutting into squares.