In a large mixing bowl, beat the softened butter with the sweetened condensed milk until light, fluffy, and homogeneous. Add the vanilla extract and mix until evenly distributed.

Gradually add the all-purpose flour in three small additions, mixing on low speed. Stop mixing when the flour is incorporated to avoid overmixing.

Wrap the dough in plastic wrap and refrigerate for at least 30 minutes.

Preheat your oven to 350°F (175°C) and line baking sheets with parchment paper.

Scoop rounded tablespoons or roll 1-inch balls from the chilled dough and place them 2 inches apart on the prepared sheets.

Bake for 10 to 15 minutes until edges are lightly golden and centers are set.

Allow cookies to cool on the baking sheets for about 5 minutes before transferring to a wire cooling rack.