This soft and fluffy ube chiffon cake is flavored by a mixture of dehydrated purple yam powder, ube halaya, and coconut milk.
Preheat oven to 325°F.
In a large bowl, whisk together cake flour, ube powder, baking powder and salt. Set aside.
In another bowl, whisk together egg yolks, half of the sugar, ube halaya, coconut milk, and oil. Mix until smooth.
Add wet mixture to dry flour mixture. Mix until thick and smooth. Set aside.
In a clean bowl, whip egg whites on low speed until foamy. Add cream of tartar and continue to whip on low speed. Add remaining sugar one tablespoon at a time while mixing. Once all the sugar has been adding, increase to medium-high speed and whip to almost stiff peaks.
Add ube extract and whip to stiff peaks.
Add whipped egg whites to cake batter in three additions. Using a sturdy spatula, gently fold in 1/3 of egg whites into cake batter. Mix until just combined.
*DO NOT OVERMIX, otherwise the egg whites will deflate.
Pour batter into an ungreased angel food cake pan. Bake for 45-50 minutes until toothpick inserted near center of cake comes out clean and top of cake springs back when touched.
Immediately invert cake pan. Allow chiffon cake to cool in pan for about 90 minutes, or until cake is room temperature.
Run a knife or a mini offset spatula around the perimeter of cake to dislodge and unmold. Remove cake from pan. Transfer to serving plate. If desired, dust with sifted powdered sugar.