Preheat Oven: Preheat your oven to 350°F (175°C). Line an 8x8 inch baking pan with parchment paper, leaving some overhang for easy removal.
Mix Wet Ingredients: In a large mixing bowl, whisk together the melted butter and granulated sugar until combined. Add the eggs and vanilla extract, and whisk until the mixture is smooth and slightly pale.
Add Dry Ingredients: Sift in the cocoa powder, flour, salt, and baking powder. Use a spatula to gently fold the dry ingredients into the wet ingredients until just combined. Be careful not to overmix.
Add Chocolate Chunks: Fold in the chocolate chunks (or chocolate chips) until evenly distributed throughout the batter.
Bake: Pour the batter into the prepared baking pan, spreading it evenly. Bake in the preheated oven for 20-25 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.
Cool and Serve: Allow the brownies to cool completely in the pan on a wire rack. Once cooled, use the parchment paper overhang to lift the brownies out of the pan. Cut into squares and enjoy!