Put the adzuki red beans in a strainer and place inside a large bowl. Rinse the beans and drain water before use. Transfer the beans to an instant pot and combine with water. Cook in high pressure for 25 minutes and let it natural pressure release once done. Drain the beans and add sugar to the pot. If needed, turn on the sauté button to help dissolve sugar completely. Once the bean paste is cool, transfer it to a container and store it in the fridge until use.

In a small saucepan, bring whole milk to a simmer over low heat. Stir in the tea powder, remove from the heat, and chill until completely cold.

In a medium mixing bowl, add the egg yolks, oil, and milk tea. Make sure to add one ingredient at a time and mix with a whisk until well-combined. Using a fine-mesh sieve, sift the cake flour into the egg yolk mixture. Fold gently to combine until fully incorporated. Do not over mix.

In a large mixing bowl, add the egg whites and lime juice and beat with an electric mixer on high until bubbly and frothy. Next, slowly pour the ⅓ of granulated sugar in three increments while the mixer is running. Continue beating the egg whites until stiff peaks form and the egg whites hold their pointed tip.

Using a rubber spatula, add about ⅓ of the egg white meringue into the egg yolk mixture and very gently fold until mostly mixed. Then transfer the mixture back to the egg white meringue and fold gently until well-mixed. Do not stir. Use the batter immediately. Pour the batter into the parchment-lined 12x17 inch pan and even out the batter with a spatula. Give the tray a few taps on your work surface to release any large air bubbles.

Bake at 400°F or 200°C for 12 minutes or until a toothpick inserted in the center comes out clean. Once you take the cake out of the oven, quickly flip the cake onto a slightly damp kitchen towel that is larger than the cake on your work surface. Peel off the parchment paper. Begin to roll the cake tightly with the kitchen towel starting with the short side of the cake. Do this very slowly and very gently. Allow the cake to cool completely rolled up in the towel.

Heavy whipping cream turns into whipped cream the fastest when the heavy cream and the bowl are both cold. Place your mixing bowl in the refrigerator for at least 10-15 minutes before making the whipped cream. Using an electric mixer or your stand mixer with a whisk attachment, whip the heavy cream and powdered sugar until medium to stiff peaks form. Add the desired amount of adzuki bean paste into whipped cream and fold gently to combine.

When the cake has cooled completely, gently unroll the cake and spread the adzuki beam cream evenly on top using a rubber spatula. Gently roll the cake back up without the towel. Tightly wrap the cake with plastic wrap or parchment paper and chill the cake in the refrigerator for 1 hour. Then garnish, slice, and serve!