1. Preheat Your Oven and Prepare Your Pan: Start by preheating your oven to 350 F (175 C). Lightly grease and flour an 8×8-inch baking pan, or line it with parchment paper, leaving an overhang on two sides to easily lift the brownies out later. This prevents sticking and makes cleanup a breeze.

2. Melt the Butter: In a large mixing bowl, melt the unsalted butter. You can do this in the microwave in 30-second intervals or on the stovetop over low heat. Make sure it’s fully melted but not boiling hot.

3. Combine Wet Ingredients: To the melted butter, add the granulated sugar and whisk until well combined. Then, crack in the two large eggs, one at a time, mixing well after each addition until the mixture is smooth and slightly lighter in color. Stir in the vanilla extract and the room-temperature sourdough discard until everything is fully incorporated. The mixture should be uniform.

4. Whisk Dry Ingredients Separately: In a separate medium bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking soda, and salt. Whisking them together ensures they are evenly distributed throughout the batter, preventing clumps of dry ingredients in your final brownies.

5. Combine Wet and Dry Mixtures: Gradually add the dry ingredient mixture to the wet ingredient mixture, stirring gently with a spatula or wooden spoon until just combined. Be careful not to overmix; overmixing can lead to tough brownies. A few streaks of flour are okay, as they will disappear during baking. If using, fold in the chocolate chips at this stage.

6. Pour into Prepared Pan and Bake: Pour the brownie batter evenly into your prepared 8×8-inch baking pan. Spread it out with your spatula to ensure it’s level.

7. Bake Until Set: Bake for 20-25 minutes, or until a toothpick inserted into the center comes out with moist crumbs attached, but not wet batter. The edges should look set, and the center might still be slightly soft, which is perfect for fudgy brownies.

8. Cool Before Slicing: Remove the pan from the oven and let the brownies cool completely in the pan on a wire rack. This is crucial for achieving that desirable fudgy texture and clean slices. Once cooled, use the parchment paper overhang to lift the brownies out of the pan and cut them into squares.