Boil 100ml water together with 2 tbsp dried osmanthus flower, off heat. Cover and leave to cool. Strain dried osmanthus flower through a fine sieve and measure osmanthus liquid to 80ml.
Sieve flour twice and mix well with chia seeds. Combine egg yolks and osmanthus sugar syrup in a bowl and mix well with a hand whisk. Combine osmanthus liquid and oil together. Blend well with the egg mixture. Add flour mixture and mix well.
Make meringue - Combine sugar and corn flour. Beat egg whites until foamy. Add half the sugar and flour mixture and continue beating for a few minutes, then add remaining sugar and flour mixture and beat until egg whites are glossy, with stiff peaks.
Fold meringue to the egg yolk mixture in 3 batches with a rubber spatula. Pour batter evenly into 20cm ungreased chiffon cake pan. Gently bang the pan on the table top to release air bubbles. (My cake was little too flat because I used a 21cm size pan)
Place cake pan in the pre-heated oven 170C and bake for about 40-45 minutes.
When cake is done, remove from oven and turn the pan over. Remove the cake from pan after cooling.
Recipe by Anncoo Journal at https://www.anncoojournal.com/osmanthus-chia-seed-chiffon-cake/