Preheat the oven to 350F and line 2 baking sheets with parchment paper.

Using a stand mixer or hand held mixer, cream the butter until it just becomes slightly fluffy. Add the flour, cornstarch, and icing sugar to the bowl and mix until everything comes together in a cohesive dough. This may take up to 5 minutes depending on the temperature of your butter. Knead in the lavender until combined.

If you aren't using a rolling pin and cookie cutter, roll the dough into 1 tablespoon balls, place them on the prepared cookie sheet and gently press down (leaving about 1" between the cookies once pressed).

Alternatively, lighlty flour a clean flat work surface and roll out the dough with a rolling pin until 2 cm thick. Use a cookie cutter or glass to gently cut out desired shapes. Transfer the cut out cookies to the baking sheet, leaving about 1" between each cookie.

Bake the cookies 10-12 minutes until the edges just begin to brown.