Beat butter and sugar together until creamy.

Put in orange zest and vanilla.

Add egg yolks and beat just until incorporated.

Include in flour and salt and beat just until incorporated.

Roll into 2 separate logs and refrigerate for at least 2 hours (can be overnight).

Preheat the oven to 350 degrees.

Remove logs and slice with a sharp knife into 1/2″ slices.

Place on a parchment-lined cookie sheet and bake for 18 minutes, or until bottoms and edges just start to brown.

Cool on wire rack.

Mix together the powdered sugar and juice of orange. Blend until smooth.

Glaze each cooled cookie and sprinkle more zest.

Allow glaze to set and serve.