Start by preheating your oven to 350°F (175°C). This ensures the brownies bake evenly and at the right temperature. Line an 8x8-inch baking pan with parchment paper or lightly grease it to make removing the brownies easier once they’re baked.

In a large bowl, whisk together the melted butter, sourdough discard, sugar, eggs, and vanilla extract until smooth and fully combined. You should end up with a glossy mixture that looks rich and inviting.

In a separate bowl, sift together the flour, cocoa powder, baking powder, and salt. Sifting is important to avoid any lumps and ensure an even texture throughout. Slowly add the dry mixture into the wet ingredients, mixing gently until just combined. Be careful not to overmix; we want these brownies to stay fudgy, not tough!

If you're using chocolate chips or any other add-ins like nuts or caramel bits, fold them into the batter now. These add-ins provide extra chocolatey pockets and texture, making each bite even more irresistible.

Pour the brownie batter into the prepared pan, spreading it out evenly. Pop the pan in the oven and bake for 25-30 minutes. Check for doneness by inserting a toothpick in the center of the brownies—if it comes out with just a few moist crumbs, they’re ready! The brownies will continue to set as they cool, so be careful not to overbake them if you prefer a gooey, fudgy texture.

Let the brownies cool in the pan for about 10–15 minutes before transferring them to a wire rack. Once completely cooled, slice them into squares and get ready to enjoy a rich, fudgy treat.