Crispy flaky taro pastry with creamy purple filling and layered crust is a dim sum favorite. A family dessert with fresh, earthy taro flavor.
Peel and cut the taro into chunks, then steam over medium-high heat for 25 minutes until fork-tender.
Mash taro while hot, then mix with 1/2 cup sugar, 1/2 stick butter, salt, and vanilla extract; cook together on low heat until a creamy, smooth filling forms. Let cool completely.
Combine 1 1/2 cups flour and 1/2 stick butter in a bowl; rub together to form coarse crumbs, then add 5 tbsp cold water and mix until a soft dough forms. Wrap and chill for 20 minutes.
In a separate bowl, mix 1/2 cup flour and shortening together until a smooth, soft paste is achieved; set aside as the oil dough portion.
Divide both doughs into 8 balls. Flatten a water dough, wrap with an oil dough ball, and roll out. Fold and re-roll twice to create flaky layers. Enclose a heap of taro filling, seal, and shape into an oval. Brush tops with egg yolk.
Bake at 375°F (190°C) for 28–32 minutes or until pastry is deeply golden and crisps up. Let cool 10 minutes before serving for optimal flakiness.