In a medium bowl, whisk flour, baking powder, and salt.
In another bowl, cream butter and sugar until light and fluffy.
Beat in eggs, vanilla extract, ube extract, and milk until smooth.
Add dry ingredients and mix until a soft, sticky dough forms.
Cover and chill the dough for at least 2 hours or overnight.
Preheat oven to 350°F (175°C) and line trays with parchment paper.
Scoop tablespoon-sized dough balls and roll with greased hands.
Coat each ball generously in powdered sugar and cornstarch mixture.
Place on baking tray spaced 2 inches apart and bake for 12–14 minutes.
Let cool on the tray for 5 minutes before transferring to a wire rack.
