In a medium mixing bowl, whisk together the all-purpose flour, baking powder, and salt until thoroughly combined. Set aside.

In a large bowl, beat the softened unsalted butter and granulated sugar with an electric mixer until light and fluffy, about 3-4 minutes.

Add in the large eggs, one at a time, mixing well after each addition. Blend in the vanilla extract and ube extract.

Gradually add the dry ingredient mix into the butter mixture, alternating with the whole milk, until a soft dough forms.

Cover the dough with plastic wrap and refrigerate for at least 2 hours or overnight.

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

Scoop tablespoon-sized portions of dough, roll into balls, and coat in a mixture of powdered sugar and cornstarch.

Arrange the dough balls on baking sheets and bake for 12-14 minutes, until edges are set and tops are slightly cracked.

Let cookies set on baking sheets for about 5 minutes, then transfer to a wire rack to cool completely.