Preheat the oven to 350°F (175°C) and grease a 9x13 inch baking pan.
Melt the butter in a saucepan over low heat.
Remove from heat, then stir in the sugar, eggs, and vanilla.
Mix in the flour, cocoa powder, and salt until just combined.
Add chocolate chips if desired and fold into the batter.
Pour the batter into the prepared baking pan.
Bake for 25-30 minutes or until a toothpick inserted comes out with a few moist crumbs.
Let the brownies cool in the pan for at least 10 minutes.
Cut into squares and serve warm or at room temperature.
Enjoy your delicious homemade brownies!