Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper to ensure your cookies come off easily.
In a microwave-safe bowl, combine the 1 cup of semi-sweet chocolate chips and 2 tablespoons of unsalted butter. Microwave in 30-second intervals, stirring after each, until melted and smooth. Allow it to cool slightly.
In another bowl, whisk together 1 cup + 3 tablespoons of all-purpose flour, 3 tablespoons of unsweetened cocoa powder, 1 teaspoon of baking powder, and 1/2 teaspoon of salt.
In a large mixing bowl, combine 1/2 cup of granulated sugar and 1/4 cup + 2 tablespoons of packed light brown sugar. Add the 2 large eggs, 2 tablespoons of whole milk, and 2 teaspoons of vanilla extract. Whisk until well combined. Slowly pour in the cooled chocolate mixture and mix until smooth.
Gradually add the dry ingredient mixture to the wet ingredients, mixing until just combined. Fold in the 1 cup of dark chocolate chips.
Using a cookie scoop or tablespoon, drop rounded balls of dough onto the prepared baking sheet, spacing them about 2 inches apart. Bake for 10-12 minutes, or until the edges are set but the centers are still soft. Remove from the oven and let them cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.
In a microwave-safe bowl, combine the 8 ounces of chopped semi-sweet chocolate and 1 tablespoon of canola or coconut oil. Microwave in 30-second intervals, stirring after each, until melted and smooth.
Once the cookies are completely cooled, dip the tops in the chocolate glaze or use a spoon to drizzle it over the cookies. If desired, sprinkle with sprinkles, chopped pistachios, or a pinch of sea salt for an extra touch.