Our tiny heart-shaped shortbread cookies are buttery-good. Make them for a Valentine's party or a tea party.
In bowl, with mixer on medium speed, beat together butter, sugar, and salt until light and fluffy, about 3 minutes. With mixer on low speed, gradually beat in flour to combine. Mix in nonpareils. Roll dough to 1/2-inch thickness between 2 sheets of parchment or wax paper, transfer to baking sheet, and refrigerate for 3 hours or up to 3 days.
Heat oven to 350°F. Transfer dough to clean surface, remove both sheets of paper, and cut out bite-size heart-shaped cookies. Place on baking sheet 1/2 inch apart and bake 14 to 18 minutes, until just golden. Transfer cookies to wire rack, and cool completely.
Brush edges of cooled cookies with corn syrup, then dip in crystal sugar.