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

Beat the softened butter and granulated sugar in a bowl until light and creamy.

Mix in the egg yolk and vanilla extract until fully combined.

Stir in the flour until a soft dough forms.

Roll the dough to 1/4-inch thickness on a lightly floured surface and cut into 3-inch circles.

Place the circles on the baking sheet and bake for 10 to 12 minutes until the edges turn lightly golden.

Cool the cookies completely on a wire rack.

Stir the powdered sugar and milk together in a bowl until smooth to create the base icing.

Spread a thin layer of white icing over each cooled cookie and let it set for a few minutes.

Place 2 tablespoons of the remaining icing in a small bowl and stir in black gel food coloring until dark.

Pipe thin black lines in a web pattern over the white icing on each cookie.