Preheat your oven to 320°F (160°C). Sift the cake flour and Earl Grey tea powder together into a bowl and set aside.
In a small saucepan, bring the 80ml of water to a boil, then stir in the 1 1/2 teaspoons of Earl Grey tea leaves. Turn off the heat, cover with a lid, and let steep for 5 to 10 minutes. Stir in the milk, then strain the mixture through a fine-mesh strainer, pressing the leaves to extract all the liquid. Let cool slightly.
Place the egg yolks in a medium mixing bowl, add 1 tablespoon (13g) of sugar, and whisk vigorously until the mixture becomes pale yellow and slightly thickened.
Pour the neutral oil and the strained, warm milk tea into the egg yolk mixture, whisking continuously until fully emulsified.
Add the sifted flour and tea powder mixture into the wet ingredients. Whisk gently until the batter is smooth and completely combined with no lumps.
In a separate, perfectly clean, grease-free bowl, beat the egg whites using a hand mixer or stand mixer on high speed. Once the whites become frothy, add 1/3 of the sugar (from the 67g allocation) and continue beating. As the meringue gains volume and thickens, gradually add the remaining sugar in two more stages. Whip until the meringue forms tight, glossy, stiff peaks.
Add 1/3 of the whipped meringue into the egg yolk batter. Use a balloon whisk to gently fold it in to lighten the base. Add the next third of meringue, switching to a rubber spatula, and gently fold from the bottom up. Fold in the final third, ensuring you scrape the bottom and sides of the bowl so the batter is completely uniform without deflating the air pockets.
Pour the cake batter smoothly into an ungreased 7-inch aluminum chiffon cake pan. Run a toothpick or bamboo skewer through the batter in a gentle swirling motion to pop any large trapped air bubbles, then smooth the top.
Bake in the preheated oven for 35 to 40 minutes, or until the top is golden-brown and a cake tester inserted into the center comes out clean.
Remove the pan from the oven and immediately invert it upside down over a bottle or cooling rack. Let the cake cool completely in this upside-down position for 1 to 2 hours before attempting to unmold.
Once completely cold, carefully release the chiffon cake from the pan by gently pressing the edges away from the mold by hand or running a thin, flexible palette knife around the perimeter and center tube.
For the decoration: Combine 1/2 cup (118g) of heavy cream(A) and 2 teaspoons of Earl Grey tea leaves in a small saucepan over medium heat. Bring to a bare simmer, then immediately cover, remove from heat, and let steep for 10 minutes. Strain through a fine-mesh sieve, pressing out the liquid, and place the infused cream into the refrigerator until chilled completely.
In a medium chilled bowl, combine the 1 cup (240g) of cold heavy cream (B) and 1/4 cup (40g) of sugar. Begin whipping to soft tracks, then stream in the cold tea-infused cream. Continue whipping until the frosting holds soft-to-medium peaks.
Coat the top and sides of the cooled chiffon cake with the Earl Grey whipped cream and decorate beautifully with pressed edible flowers.