Preheat your oven to 350°F (180°C) and line a square baking pan (8x8 inches) with parchment paper, allowing some overhang for easy removal. Lightly coat the parchment with cooking spray.

Chop the semi-sweet chocolate. Add it to a microwave-safe bowl along with the stick of butter. Microwave using 30-second intervals, stirring between each heating time. Total it should take 1 minute and 30 seconds in total. The chocolate mixture should be smooth and melted.

Add the white sugar and brown sugar. Whisk until smooth and well combined. Add the eggs and vanilla extract, then beat until the mixture is thick and light.

In a medium bowl, add the all-purpose flour, cocoa powder, instant coffee granules, and baking powder. Whisk to combine. The coffee step intensifies the chocolate flavor, making it a perfect treat for coffee lovers.

Gradually fold the dry ingredients into the wet mixture. Avoid overmixing to maintain the fudgy center.

Optionally fold in the chocolate chunks or chips for extra bursts of chocolate in each bite.

Pour the brownie batter into the prepared pan and smooth the top. Bake in the preheated oven for 30-35 minutes, or until a toothpick inserted in the center comes out with moist crumbs (for extra fudgy brownies) or clean (for a more set texture).

Cool and Serve. Let the brownies cool in the pan for about 10 minutes, then lift them out using the parchment paper and transfer to a wire rack to cool completely.

For the ultimate experience, dust with powdered sugar or top with a scoop of vanilla ice cream before serving.