Heat the oven to 350 degrees F and line a baking sheet with parchment paper.

In a medium bowl, whisk together the flour, matcha powder, baking powder, and salt.

In a separate bowl, beat the softened butter and sugar until light and creamy.

Add the egg yolk and vanilla extract to the butter mixture and stir until smooth.

Combine the wet and dry mixtures and mix until a soft dough forms.

Scoop tablespoon-sized portions of dough onto the prepared baking sheet and gently flatten each one.

Bake for 10 to 12 minutes until the edges are set.

Let the cookies cool on the sheet for 5 minutes, then move them to a wire rack.

Melt the dark chocolate chips in the microwave in 20-second bursts, stirring between each.

Use a small spoon or piping bag to draw simple faces on the cooled cookies with the melted chocolate.