Shortbread cookies are surprisingly easy to make and they are really yummy. I chose to make mini shortbread instead of one large --- mostly so that I wouldn't eat the entire thing in one sitting.
1/2 cup old fashioned oats
1 1/2 cups flour
1/4 cup cornstarch
2/3 cup powdered sugar
1/2 teaspoon salt
14 Tablespoons butter, cold, sliced into 1/8" thick slices
1 Tablespoon lemon zest
Pulse oats in food processor until ground to a fine powder.
In bowl of standing mixer, combine oat flour, flour, cornstarch, sugar , lemon zest and salt.
Turn oven off. Remove springform collar.
Use chef's knife to score surface of shortbread into 6 equal pieces, cutting halfway through shortbread.