Add vanilla,salt and beat again till its well incorporated.
In another bowl,flour the choco chips and walnuts.This is done so that the nuts andchoco chips do not sink while baking the brownies.
Now,add flour and cocoa powder to the egg mixture and use a wooden or silicon spatula to mix.Mix well to avoid any lumps.
Now,add the melted chocolate and butter mix and mix till well blended.Add the floured choco chips and walnuts.Pour this mixture in a already lined 12 inch by 9 inch baking tray and let the butter paper or foil remain a bit extra on the sides to easily pull it out post baking.
Bake @ 180 Celsius for 25-30 minutes or till done.Do check after 20 minutes once to avoid over baking .you may have to bake longer in case its not done as it differs per oven.do bake till done.
Let it cool completely before cutting it.
TIPS:
Always cut the brownies with a plastic knife to save the edges from crumbling.
All ingredients must be at room temperature for an even cooking.
Please keep checking in the last 10 min as over baking just kills the brownie.