1 cup (228g) unsalted butter, at room temperature
1/2 cup (110g) light brown sugar, packed
1 egg yolk
1 teaspoon fresh rosemary, finely chopped
1 teaspoon almond extract
1 teaspoon lemon zest or 1/2 teaspoon lemon extract
1+1/2 cup (210g) all-purpose flour
1/2 cup (65g) cornstarch
3/4 teaspoon kosher salt
1/2 teaspoon baking powder

In a large bowl, with a hand mixer, cream the butter until light and pale (about 3-4 minutes). Add the sugar and beat for another 3-4 minutes or until light and fluffy. Reduce speed to low and add the egg yolk, almond extract, lemon zest/extract, and rosemary and beat until thoroughly combined. In another bowl, sift together flour, cornstarch, salt, and baking powder. Add the flour mixture to the sugar mixture and mix until a uniform dough is formed. Scrape the dough on to a piece of plastic wrap and form it into a disk with an 8″ diameter that is 1″ thick. Refrigerate for 20 minutes or until it is firm enough to roll out. At this point, preheat the oven to 325 degrees. On a floured work surface, roll out the dough to be 1/4″ thick. A trick I use is buying 1/4″ wood dowels and lining them up on either side of the dough as bumpers for my rolling pin. Cut the dough into any shape you want using either a knife or cookie cutters! Arrange shortbread cut outs on a baking sheet about 2″ apart. Bake for 18-20 minutes or until the short breads are just golden brown. Let cool on a baking sheet for 15 minutes before transferring to a wire rack to cool completely.