1. Preheat your oven to 350 F (175 C). Lightly grease an 8×8 inch square baking pan or line it with parchment paper, leaving an overhang on two sides to easily lift the brownies out later.

2. In a large mixing bowl, melt the unsalted butter. Add the granulated sugar to the warm butter and whisk until well combined. Crack in the two large eggs, one at a time, whisking well after each addition until fully incorporated. Stir in the vanilla extract and the sourdough discard until the mixture is smooth and uniform.

3. In a separate medium bowl, combine the all-purpose flour, unsweetened cocoa powder, baking powder, and salt. Use a whisk to thoroughly mix these dry ingredients together.

4. Gradually add the dry ingredient mixture to the wet ingredient mixture in the large bowl. Using a spatula or wooden spoon, mix until just combined. Do not overmix.

5. Gently fold in the chocolate chunks or chips into the brownie batter. Distribute them evenly throughout the batter.

6. Pour the brownie batter into your prepared 8×8 inch baking pan. Use your spatula to spread the batter evenly to the corners of the pan. Place the pan in the preheated oven and bake for 25-30 minutes. The brownies are done when a toothpick inserted into the center comes out with moist crumbs, but not wet batter.

7. Once baked, remove the brownies from the oven and place the pan on a wire rack to cool completely. Allow them to cool for at least 20-30 minutes, or even longer, to help them set up and become perfectly fudgy. If you used parchment paper, you can lift the cooled brownies out of the pan and onto a cutting board for easy slicing. Cut into squares and serve.