Preheat oven to 325 degrees (F).

In a food processor, combine flour, cornstarch, sugar, salt and dried flowers, pulsing until well combined.

Add butter and pulse until the mixture resembles wet sand and holds together slightly if pressed between fingers. (If no food processor, use a pastry cutter, fork or fingers to cut in butter thoroughly)

Press into the bottom of a 8" round tart pan with removable bottom (or your preferred baking dish of similar size) using the bottom of a measuring cup or something flat. Make sure all the edges are pressed firmly as well.

Bake for 20-25 minutes, until the very edges are barely golden and the surface of the shortbread appears "dry". Remove from oven, dust lightly with sugar, and immediately cut or score into preferred servings. Cool completely before removing from baking dish.