Preheat the Oven – Set to 350°F and line a baking sheet with parchment paper.
Cream the Butter – In a large bowl, beat the butter with a mixer for about 5 minutes, until it turns lighter in color and fluffy.
Incorporate the Sugar – Gradually add powdered sugar, mixing until smooth.
Combine Dry Ingredients – In a separate bowl, whisk together the flour, cornstarch, and baking powder.
Mix Dough – Slowly blend the dry ingredients into the butter mixture, ensuring everything is well combined with no lumps.
Chill the Dough – Refrigerate for at least 30 minutes to firm up.
Shape the Cookies – Scoop small portions (about 1 ½-inch balls) and roll them between your hands. If the dough is sticky, dust your hands lightly with flour.
Arrange on Baking Sheet – Place dough balls 2 inches apart on the lined sheet.
Bake – Let them bake for 18 to 20 minutes, just until the edges show a hint of golden brown.
Cool – Leave them on the baking sheet for 10 minutes before transferring to a wire rack, as they are very delicate when warm.