Preheat the oven to 350°F. Grease a 8x8-inch baking pan or line it with parchment paper.
In a medium saucepan, melt the butter and semi-sweet chocolate chips together over medium heat, stirring constantly. Once melted and smooth, remove from heat.
Whisk in the brown sugar and allow to cool slightly.
In a large bowl, whisk together the melted chocolate mixture, eggs, and vanilla extract until well combined. Mix in 1 cup of Nutella until fully incorporated.
Whisk in the flour, cocoa powder, and salt gradually, mixing until just combined.
Stir in the chopped hazelnuts.
Pour the brownie batter into the prepared pan and spread it evenly.
In a small bowl, microwave the remaining ½ cup of Nutella until just melted (about 20-30 seconds). Drizzle the melted Nutella over the top of the brownie batter. Use a knife or a skewer to gently swirl the Nutella into the batter.
Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Notes
These brownies can be stored at room temperature in an airtight container for up to 3-4 days. If you want them to stay fresh longer, refrigerate them for up to a week. You can also freeze them for up to a month.
Chopping the hazelnuts into smaller pieces helps them distribute more evenly throughout the brownies. You can toast them lightly for added flavor, but make sure they cool before adding to the batter.
The key to fudgy brownies is underbaking slightly. Start checking at 25 minutes to ensure they're not overdone. The brownies will firm up as they cool.
If you’re baking for a large crowd, you can double the recipe and bake in a 9x13-inch pan. Just remember to adjust the baking time (about 10-15 minutes longer), and check doneness by inserting a toothpick.
When combining the dry ingredients with the wet mixture, mix just until incorporated. Over mixing can result in dense, tough brownies rather than soft and fudgy ones.
FAQs
Can I make these brownies gluten-free?Yes! You can make these brownies gluten-free by swapping the all-purpose flour with a gluten-free flour blend. Be sure to check that the chocolate chips and Nutella you’re using are gluten-free, as some brands may contain gluten.Can I skip the hazelnuts?Absolutely! You can skip them entirely or substitute them with other nuts like walnuts, almonds, or pecans. You can also opt for chocolate chips or leave the nuts out for a smoother texture.How do I prevent the Nutella swirl from sinking to the bottom?To prevent the Nutella from sinking, make sure the brownie batter is thick enough before you add the swirl. Don’t add too much melted Nutella at once; drizzle it lightly over the surface and swirl gently.