1. Preheat oven to 175 degrees C.
2. Line an square pan with a parchment paper
3. In a large bowl, whisk the butter, brown sugar, and white sugar until combined. Add the eggs and vanilla essence whisking again until combined.
4. Add in 1 cup of the nutella mixing until combined.
5. Sprinkle the flour, cocoa powder and lindt chocolate over the batter, then stir just until combined.
6. Pour the brownie batter into the baking pan, spreading it evenly into the corners. Drop teaspoonfuls of the remaining nutella. Using a knife or spoon to swirl the Nutella into the batter.
7. Bake for 30 minutes.
8. Let the brownies cool completely before slicing into squares. You could easily add some chopped pecans or hazelnuts into the mixture.

Some tips when making a brownie:

• Always use room temperature eggs and melted butter.
• Don’t over mix your batter, you want to fold in your chocolate pieces and nuts.
• Wait for your brownies to completely cool before cutting.
• Nigellas tip- Brownies should be removed from the oven before the centre is fully cooked, as the brownies will continue to set as they cool and this gives the brownie its soft texture. You do not want the brownies to be raw in the centre when you remove them from the oven, but they should be slightly undercooked. If you insert a cake tester into the centre of the brownies pan it should come out with some damp crumbs attached. If the tester has raw batter on then bake for another 2-3 minutes and test again. Brownies go very quickly from being fudgy to cakey, so if in doubt start checking them slightly early.