Lemon Sables

This recipe is an elaboration of our basic shortbread cookie recipe. Besides the flavoring, we only use three ingredients to make shortbread:

Flour : to provide structure and strength to the cookies. Flour is mostly starch but it also has protein (gluten) that we can manipulate to produce firm and chewy bread or soft and tender cakes. To develop the gluten in the flour, we must add moisture and then mix the dough. The moisture in our shortbread cookies comes from the water content of the butter (15% water and 85% fat). The more we mix the dough/batter, the more gluten develops. In making bread, we knead the dough so that the gluten forms long elastic strands that will trap carbon dioxide (from the yeast) in tiny pockets and make the bread rise and yield a firm and chewy crust. We don't want that when we make cookies. The more we work the dough, the tougher the cookies. We add the flour last and mix it just until combined.

Different flours differ in gluten content; bread flour has a lot and cake flour not too much. Many cookie recipes call for all purpose flour, which falls in between bread and cake flour.

Butter in shortbread cookies not only adds moistness and richness, it acts as the glue to sugar and flour. Also, the fat in butter increases the shelf life of the cookies.

Sugar adds sweetness and crust color (as it caramelizes with heat). It creates tenderness and fineness of texture and also increases the shelf life of products by retaining moisture.

So now, we are going to alter this shortbread recipe by adding egg yolks. The yolks increase the fat, protein, and moisture content of the cookies. The fat "shortens" the dough by weakening the gluten network thus yielding more tender and crumbly products. Most importantly, the addition of yolks binds the dough together so that we can easily roll it up into a log. And here we have a recipe for:

Lemon Sables

8 oz unsalted butter (cold, cut up into small pieces)
1/2 c sugar
2 egg yolks
2 1/4 c flour (all purpose)

as flavorings, we will add:
2 T lemon zest
a pinch of salt

Place the butter and sugar in the KitchenAid bowl. Using the paddle attachment, mix on low speed just until the butter combines with the sugar. Beat in the egg yolks one at a time until well incorporated. Add the flour, lemon zest, and salt. Mix until just combined. Divide the dough in half. Shape each half into a 1 inch diameter log.

Roll in raw sugar, granulated sugar, candy sprinkles, or chopped nuts. Or you can leave it plain.

Wrap a piece of parchment or wax paper around the dough and use a ruler to press the paper tight around it.

Chill the dough until firm. Slice the cookies 1/4 inch thick, rotating the roll of dough often to keep the log from getting squashed and misshapen from the weight of the knife.

Place the cookies an inch apart and bake at 350F for 12 to 15 minutes, until the cookies are firm to the touch.