Lavender Shortbread Cookies

Ingredients

• 1 1/2 cups butter, softened
• 2/3 cup white sugar
• 1/4 cup sifted confectioners' sugar
• 2 tablespoons finely chopped fresh lavender
• 1 tablespoon chopped fresh mint leaves
• 1 teaspoon grated lemon zest
• 2 1/2 cups all-purpose flour
• 1/2 cup cornstarch
• 1/4 teaspoon salt