Preheat the oven to 350 degrees F and line a large baking sheet with parchment paper.

In a large bowl, mix together the flour, sugar and cornstarch. (Add lemon zest and lavender to the flour mixture if making the variation, see notes below). Add the butter and mix with your hands into a soft dough.

Divide the dough into four equal parts (approximately 152g each) and shape into four discs about 1 inch high. Using a sharp knife or a bench scraper, cut each disc into eight equal wedges, then score the larger end with a fork.

Bake for 20 minutes or until just barely golden brown on the bottom and edges. While the cookies are still warm re-cut into wedges then let cool for 5-10 minutes before transferring to a cooking rack.