Cream the butter in a stand mixer until smooth and a very pale yellow color (no longer bright yellow), about 2 minutes. I take a spatula and scrape down the sides halfway through to ensure even, full mixing.

Add the sugar and mix until well blended, about 1-2 full minutes. I scrape down the sides of the mixer twice during this time to ensure even mixing.

In a separate bowl, mix together flour, cornstarch and salt. Slowly add to the mixer and mix on low until all dry and wet ingredients are combined.

Gently pick the lavender off the stems until you have almost a Tablespoon full.

Add lavender into the mixer and mix the dough until it starts to come together and pull away from the sides. It should not be crumbly.

Sprinkle a little powdered sugar onto a rolling mat or cutting board and knead the dough gently but thoroughly, about 5-7 times.

Roll out the dough into a circle until the circle is about ¼" thick.

Using a cookie cutter, cut out 2" shapes.

Place cut cookies onto a baking sheet with either parchment paper or a Silpat. Sprinkle lightly with granulated sugar.

Take a toothpick or a fork and gently poke small holes into the cookie. This helps the cookies bake evenly and not puff up.

Bake at 350 degrees for 15-20 minutes, until cookies have very light golden edges. Make sure they are not too dark, and watch them carefully: shortbread can burn quickly toward the end! My batches took around 17 minutes.