French sablé cookies are very easy to make because they are slice-and-bake cookies. These vanilla butter cookies are made with very simple ingredients that you surely have on hand.
In the bowl of an electric mixer fitted with the paddle attachment, cream the butter, salt, and sugar.
Add the yolk and beat, scraping down the sides as needed, then add the vanilla.
Add the flour and mix just until combined.
Turn out the dough on a work surface and form a log with ~2 inch diameter (you can roll it in coarse raw cane sugar or sanding sugar to give your cookies a crunchy sugary edge), then wrap the log in plastic wrap and refrigerate several hours, or overnight.
Preheat the oven to 350°F (175 °C). Slice the log into ¼ inch slices and arrange on a parchment lined baking sheet.
Bake for about 15–20 minutes, or until the edges just begin to turn golden. Cool on a wire rack before serving.