Sift the flour, whey, matcha and salt together into a large bowl.
Place the butter and sugar in a bowl of a stand mixer fitted with the paddle attachment and beat until light and fluffy.
Reduce the mixer speed to low and slowly add the flour mixture. Beat until just incorporated.
Turn the dough out onto a large piece of plastic wrap, form into a 2" wide log shape, wrap and place in the refrigerator to chill for 1 hour.
Preheat oven to 350 degrees.
Remove dough from the refrigerator. Using a sharp knife, slice into rounds about 1/4" to 1/3" thick and place on a parchment or silpat lined baking sheet.
Bake for 10-12 minutes until edges just start to turn golden brown. Remove and let cool on baking sheet for a couple of minutes before transferring to a cooling rack to cool completely.
Melt the chocolate chips and coconut oil and stir until smooth.
Drizzle the chocolate over the cookies as desired and let set for a few minutes to harden. You can place them in the refrigerator for 10 minutes to speed this process up.