1 cup (250 mL) unsalted butter, softened
½ cup (125 mL) icing sugar, sifted
¼ cup (60 mL) cornstarch
1 tsp (5 mL) vanilla extract
½ tsp (2 mL) salt
1 ½ cup (375 mL) all-purpose flour
coloured sprinkles (optional)
1. In large bowl with electric beaters, beat butter, sugar, cornstarch, vanilla and salt until fluffy; mix in flour just until combined. Cover bowl and refrigerate just until firm, about 20 minutes.
2. Roll by tablespoonfuls into balls; place on parchment paper-lined baking sheets. Using lightly floured tines of fork, press tops of cookies until flattened to ½-inch (1 cm). Top with sprinkles, if using.
3. Bake in preheated 300°F (150°C) oven until pale golden and just set, 14 to 16 minutes. Let cool on pans on racks for 10 minutes; transfer cookies to racks and let cool completely (store in airtight container for up to 2 weeks).