Preheat your oven to 350°F (175°C). Prepare two baking sheets by lining them with parchment paper to prevent sticking.
In a medium-sized microwave-safe bowl, add the semi-sweet chocolate chips and cubed butter. Microwave the mixture in 30-second intervals, stirring each time, until the chocolate and butter blend together into a smooth and shiny consistency. Allow it to cool for a few moments.
In a large mixing bowl, add the granulated sugar, eggs, and vanilla extract. Using a whisk, beat the mixture until it becomes light in color and fluffy in texture, which should take about 2-3 minutes.
Carefully pour the warm, melted chocolate mixture into the fluffy sugar and egg mixture. Stir until everything is thoroughly combined, ensuring no chocolate streaks remain.
Sift the all-purpose flour, unsweetened cocoa powder, baking powder, and salt into the chocolatey mixture. Gently stir the dry ingredients in until just combined, being cautious not to overmix as this can affect the texture.
If you desire added crunch, fold in the chopped walnuts or pecans at this stage until evenly distributed throughout the dough.
Using a tablespoon, scoop heaping portions of dough onto the prepared baking sheets. Ensure to space each dollop about 2 inches apart to allow room for spreading during baking.
Place the baking sheets in the preheated oven and bake for 10 to 12 minutes. Look for slightly set edges and soft centers to ensure that fudgy texture you crave! Avoid overbaking!
Once baked, remove the cookies from the oven and let them cool on the baking sheets for about 5 minutes. Afterward, transfer them to a wire rack to cool down completely.
Notes
Elevate your serving by dusting the cooled cookies lightly with powdered sugar for a snowy effect.