In a small saucepan melt butter over low heat, set aside
Roughly chop 8oz chocolate bar
Add chopped chocolate and vanilla extract into melted butter, and stir
Allow chocolate to completely melt, set aside and allow to cool
Preheat oven to 350 °F
On a baking sheet lined with parchment paper add the walnuts in a single layer, bake for 5 to 10 minutes, or until golden brown
Allow walnuts to cool completely and roughly chop, set aside
In a stand mixer bowl beat eggs and sugar together for approximately 2 to 3 minutes
Stir cooled chocolate into eggs and sugar, mix until completely combined
Using a fine mesh sieve sift all purpose flour, baking powder and salt together
Add sifted flour mixture into the wet ingredients in thirds, mixing between each addition until all dry ingredients are completely incorporated
Gently fold chopped walnuts into brownie batter
Line 9”x9” square pan with parchment paper
Pour brownie batter into the pan, using the offset spatula smooth brownie batter ensuring it is evenly distributed in the pan
Bake for approximately 50 to 60 minutes, or until a tester inserted in the center comes out clean
Allow brownies to cool in pan for approximately 20 minutes before removing
Transfer brownies to a wire cooling rack to completely cool
Slice and enjoy