Lavender Rice Flour Shortbread

Place the dried culinary lavender and one tablespoon of the icing sugar into a mortar and pestle or spice grinder. Grind thoroughly until the lavender is finely powdered to prevent unpleasant, soapy textures in the final cookie.

In a stand mixer fitted with a paddle attachment, combine the softened unsalted butter, the remaining icing sugar, and the pulverized lavender-sugar mixture. Cream on medium speed until pale and fluffy.

Pour in the vanilla extract, if using, and beat briefly just until incorporated into the butter mixture.

Sift the all-purpose flour, white rice flour, and fine sea salt directly into the mixing bowl. Mix on the lowest possible speed until the dough just begins to clump together. Do not overmix, as this will activate gluten and toughen the shortbread.

Turn the dough out onto a large sheet of parchment paper. Knead it gently by hand once or twice to bring it together into a cohesive block, then roll it out to an even 1-centimeter thickness. Transfer the parchment and rolled dough to the refrigerator to chill thoroughly.

Preheat the oven to 150°C (300°F).

Remove the firm, chilled dough from the refrigerator. Cut into 5-centimeter rounds or classic rectangular fingers. Place the cut cookies onto a parchment-lined baking sheet, spacing them about 2 centimeters apart.

Bake in the preheated oven at 150°C (300°F) for 25 to 30 minutes. The cookies are done when the edges are just barely beginning to take on a pale golden color, but the centers remain quite pale.

Allow the shortbread to cool on the warm baking sheet for 10 minutes to allow their structure to set, then carefully transfer them to a wire cooling rack to cool completely to room temperature.