**Preheat Oven:** Preheat your oven to 350°F (175°C). Line baking sheets with parchment paper or silicone baking mats.

**Melt Chocolate and Butter:** In a microwave-safe bowl, melt the semisweet chocolate chips and butter together in 20-second intervals, stirring between each interval until smooth. Let cool slightly.

**Mix Wet Ingredients:** In a large mixing bowl, beat the sugar, eggs, and vanilla extract with an electric mixer until thick and pale, about 3 minutes.

**Combine with Chocolate:** Gradually mix the melted chocolate mixture into the wet ingredients until fully incorporated.

**Mix Dry Ingredients:** In a separate bowl, whisk together flour, cocoa powder, baking powder, and salt. Gradually add the dry ingredients to the wet mixture, stirring until just combined. Fold in mini chocolate chips if using.

**Portion Cookies:** Using a spoon or cookie scoop, drop tablespoon-sized portions of dough onto the prepared baking sheets, spacing them about 2 inches apart.

**Bake:** Bake for 8-10 minutes, or until the tops are shiny and crackly. The cookies will be soft but will firm up as they cool.

**Cool:** Allow the cookies to cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.