1. Start by preheating your oven to 350°F (175°C) and preparing a baking pan with parchment paper, leaving some overhang for easy removal.
2. In a medium saucepan over low heat, melt unsalted butter. Add sugar and cocoa powder, stirring until the mixture is smooth and cohesive. Ensure not to overheat.
3. Sift all-purpose flour and salt together in a separate bowl to break up any lumps and ensure even distribution.
4. Remove the saucepan from the heat and let it cool slightly. Add eggs, one at a time, whisking quickly to incorporate without cooking them. Stir in vanilla extract for added flavor.
5. Gently fold the dry mixture into the wet mixture, combining just until incorporated without overmixing to maintain a fudgy texture.
6. If desired, fold in optional add-ins like chocolate chips, walnuts, espresso powder, or coffee granules for extra flavor and texture.
7. Pour the batter into the prepared pan and smooth it out with a spatula. Bake for about 25 to 40 minutes, depending on your desired level of fudginess. A toothpick inserted should come out with moist crumbs but not wet batter.
8. Let the brownies cool completely in the pan to allow the center to set. Then, use the parchment paper overhang to lift the brownies out and cut into squares. Enjoy your rich, fudgy brownies with shiny crusts!