01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together flour, cocoa powder, baking powder, baking soda, and salt until well blended.
03 - In a large bowl, beat softened butter, granulated sugar, and brown sugar with an electric mixer until light and fluffy, approximately 2-3 minutes.
04 - Add eggs one at a time, beating thoroughly after each addition until fully incorporated.
05 - Mix in milk, vanilla extract, white vinegar, and green food coloring until completely combined and uniform in color.
06 - Gradually add dry ingredients to wet mixture, mixing until just combined. Take care not to overmix to maintain tender texture.
07 - Using a cookie scoop or tablespoon, drop dough onto prepared baking sheets, spacing approximately 2 inches apart to allow for spreading.
08 - Bake for 10-12 minutes until edges are set but centers remain slightly soft.
09 - Let cookies rest on baking sheets for 5 minutes, then transfer to wire rack to cool completely before drizzling.
10 - Melt white chocolate with oil (if using) in microwave-safe bowl in 20-second intervals, stirring between each until smooth and fluid.
11 - Drizzle melted white chocolate over cooled cookies using fork or piping bag. Allow chocolate to set before serving.