Preparation Steps

• Sift the cornstarch into a bowl to aerate it and remove any lumps.
• Measure out all remaining ingredients and set them nearby.
• Preheat the oven to 350°F.
• In a medium bowl, combine the softened butter, sweetened condensed milk, vanilla extract, egg yolk, and salt. Mix until smooth.
• Gradually fold the sifted cornstarch into the wet mixture until a dough forms.
• Roll the dough into walnut-sized balls and place them on parchment-lined baking sheets.
• Refrigerate the sheets for 30 minutes to prevent spreading during baking.
• Bake for 12-15 minutes, until edges are golden but centers remain pale.
• Let the cookies cool on the baking sheet for 20 minutes before transferring them to a wire rack.