Pre heat oven to 325F. Then lightly grease baking pan with melted butter or line with parchment paper. In a large mixing bowl, sift flour, and cocoa powder together.
Combine butter, half amount of sugar, salt and grape seed oil in a small sauce pan and melt over medium low heat.
Combine eggs, remaining sugar, vanilla extract, salt in a medium mixing bowl. Whisk until everything combine and has a pale light color.
Add ⅓ amount of butter mixture into the egg mixture, whisk vigorously to temper the egg mixture and prevent it to become scrambled. Then carefully stir the tempered egg mixture back to the butter mixture.
Gently fold the sifted flour mixture into the wet ingredients until just combined.
Spread the batter evenly onto a baking pan. The pan will be almost half full. Bake until the center is set, approximately 20 minutes.
Allow brownies to cool completely before cutting into 12 small squares.