Preheat the oven to 325°F (163°C). Prepare a 9-inch chiffon pan without greasing it.

Whisk together the egg yolks and half of the sugar until pale and creamy. Add milk, oil, vanilla, taro, and ube halaya; mix until smooth.

In a clean bowl, whip egg whites with a pinch of salt. Gradually add remaining sugar and cream of tartar until stiff peaks form.

Gently fold one-third of the whipped egg whites into the yolk mixture, then carefully fold in the remaining egg whites until no white streaks remain.

Pour the batter into the chiffon pan, smoothing the top. Bake for 30-35 minutes until golden and springs back to touch.

Immediately invert the pan onto a bottle to cool upside down for about an hour.

Once cool, run a knife around edges to release the cake. In a bowl, whip ube halaya with cream until fluffy and spread over the cake.