01 -
Line an 8x8-inch baking pan with parchment paper, leaving a 1-inch overhang on each side for easy removal later.
02 -
In a large bowl, combine the softened butter, granulated sugar, salt, and vanilla extract. Using a hand mixer or stand mixer with paddle attachment, beat on medium speed until light and fluffy but not overly whipped, about 2 minutes.
03 -
Add the flour to the butter mixture and mix until just combined. The dough should look crumbly, similar to pie dough. If overmixed, the cookies will become tough.
04 -
Transfer the dough to the prepared baking pan. Use your fingers to lightly press the dough evenly into the pan to about ½ inch thickness. Cover with plastic wrap and use a spatula to smooth the top completely.
05 -
Remove the plastic wrap and use a fork to put shallow pricks on the surface (about 36 evenly spaced pricks). This technique, called docking, allows steam to escape during baking. Chill the dough for 30 minutes in the refrigerator or 15 minutes in the freezer.
06 -
While the dough is chilling, position an oven rack in the middle and preheat to 325°F (165°C).
07 -
Bake the chilled dough for 30-35 minutes, until the surface is golden brown. The biscuits should be just under an inch thick when baked.
08 -
Allow the biscuits to cool for just 5 minutes after removing from the oven, then carefully slice into rectangles using a sharp paring knife. For 18 pieces, cut them into approximately 2.6 by 1.3 inch rectangles.
09 -
While the biscuits are still warm, sprinkle additional granulated sugar over the top. The warmth helps the sugar adhere better to the surface. For a shiny appearance, use sparkling sugar or coarse sanding sugar.
10 -
Let the biscuits cool completely in the pan before serving. Although tempting to eat immediately, the texture is best when fully cooled, as the butter solidifies for a slightly crisp yet delicate bite.