Preheat the oven to 350°F. If you want chewy and moist brownies, use a 13 × 9 × 2-inch pan; if cakey, a 9-inch square pan. Grease the pan and line with parchment paper so it extends over the long sides.
In a small saucepan, melt butter and unsweetened chocolate. Once melted, allow to cool, or your brownies will be heavy and dry.
Beat in a large bowl eggs and salt until light in color and foamy in texture.
Gradually add sugar and vanilla and continue beating until thick
With a few swift strokes stir in the cooled chocolate mixture just until combined. Even if you are using an electric mixture, switch to a wooden spoon for this.
Stir in flour until just combined, then gently fold in pecans (is using)
Scrape the batter into the prepared pan. Bake about 25 minutes or until a toothpick inserted in the center comes out clean or with moist crumbs attached. Let cool completely in the pan on a rack.