In a medium bowl, whisk together all of the dry ingredients: all-purpose flour, baking soda, and salt.
In a stand mixer using the paddle attachment (can alternatively use hand mixer or whisk), mix the butter, sugars, and vanilla on medium speed until combined. Scrape bottom of bowl. Add milk and matcha powder, mixing until smooth.
Dump in all of the dry ingredients and mix until no dry spots remain. Cover the dough and let it rest in the fridge for 20-30 minutes. This will let the flour hydrate and let the butter cool, yielding chewier cookies.You can skip ahead during this time to make the chocolate ganache.
Preheat oven to 350°F/177°C and line two baking trays with parchment paper or silicone mats.
Use small cookie dough scoop to gather dough (about 1 ½ tablespoon each). Roll into a ball and shape onto lined baking tray. Using your fingers, shape the ball of dough into a teardrop/pear (see picture in post for reference). Place avocados about 3-4 inches apart.
Bake for 10-13 minutes. Cookies should look slightly puffy and soft in the center, in addition to retaining their green color. The edges should be set/firm, slightly browned.
As soon as you remove the cookies from the oven, use the back of a metal teaspoon/tablespoon to create a circular indent. The ganache will later go in the indent to create the "avocado seed". If you want, you can also shape the edges by pushing them with rubber spatula to get a more perfect avocado shape.
Let cool on pan for about 5-10 minutes, then transfer to wire rack. Let cool completely.
For the chocolate ganache:
Microwave for 45 seconds, then mix. If the chocolate is not fully melted, microwave at 10-second intervals and mix until it is smooth.
Place bowl into the fridge and stir it every 10 minutes until the ganache is thick enough to pipe, about 30-45 minutes. Transfer ganache to a ziploc or piping bag and snip a medium tip.
Decorating:
Pipe chocolate ganache in cookie indents to create the avocado seed.
Use melted chocolate for the eyes, smile, and cookie outline.
Add oil-based red or pink food coloring to the melted white chocolate. If you don't have oil-based food coloring, then the chocolate will seize/become lumpy.To counter this, stir in a tsp of neutral oil (canola, vegetable) at a time, until it becomes smooth again. Use this for the blush.
Enjoy!
Notes
Store cookies in an airtight container at room temperature for up to a week.