Preheat the oven to 325° F. Cover two baking sheets with parchment or brown paper.
In a large bowl with an electric mixer, cream together the butter, sugar and lavender until light and fluffy, about 3 minutes. Add the flour, cornstarch, and salt; beat until combined.
Divide the dough in half. Flatten it into squares and wrap it in plastic. Chill in the refrigerator until firm, approximately 1 hour.
On a floured board, roll or pat out each square to a thickness of 3/8-inch. Cut the dough into 1 1/2-inch rounds or into a shape of your choice with a cookie cutter.
Transfer the cookies to the prepared baking sheets, spacing the cookies about 1 inch apart. Prick each cookie several times with the tines of a fork. Bake 20 to 25 minutes until pale golden (do not brown). Cool slightly, then transfer to a rack. Allow the cookies
To make the frosting, cream together the softened butter and the lemon zest. Begin adding small amounts of the sugar and the lemon juice, mixing well before adding more.
Use a knife to spread the frosting on the cooled cookies. Before the frosting hardens, sprinkle lavender buds on top of each cookie.
This cookie recipe is excerpted with permission from <a href="http://www.amazon.com/gp/product/1604692219/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1604692219&linkCode=as2&tag=craftfocom-20">"The Lavender Lover's Handbook: The 100 Most Beautiful and Fragrant Varieties for Growing, Crafting, and Cooking"</a> by Sarah Berringer Bader and published by Timber Press. Image from Janet Loughrey.