Preheat oven to 160 degrees C (320 F). Line the bottom of each cake pan with two layers of parchment (see footnote 2). Grease the walls of each cake pan with grapeseed oil. Set aside.

Combine matcha powder, 1 tablespoon and 1 teaspoon of hot water in a small bowl, stir with a spoon until matcha powder is fully dissolved in the water. Add 2 tablespoons of cool water and whisk until matcha is thoroughly mixed.

In a large bowl, combine egg yolks and sugar. Whisk until the sugar is fully dissolved and incorporated into the egg yolk.

Add oil and whisk until fully combined.

Use a spoon to stir the matcha mixture several times, then add it into the large bowl. Whisk several times until matcha is mixed evenly.

Add cake flour and whisk until fully incorporated. It’s OK if there are some lumps in the mixture.

In another clean medium sized bowl, add the egg whites. Whisk with an electric mixer at low speed until the egg white starts foaming, about 1 minute. Stop mixer and add lemon juice (see footnote 3).

Mix at medium speed until the foam bubbles become tiny, firm and even, about 3 minutes. Add sugar slowly and mix at high speed until the mixture has a firm peak when you lift the mixer from the mixture. From here, you should move as quickly as you can in the following steps.

Add half of the egg white mixture into the egg yolk mixture. Use a whisk to mix gently, until the egg white is just mixed.

Add the rest of the egg white mixture and continue to mix, until fully incorporated.

Use a rubber spatula to fold the batter gently, until the batter becomes a consistent, pale green color without any obvious dark green spots.

Pour the batter into the cake pans. The batter should almost fill the pans. Bake on the middle oven rack for 20 minutes. Check the cake. If the surface turns brown, move the cake pans to the bottom rack and continue to bake until cooked through, about 10 minutes. Use a toothpick to pierce the middle of the cake. The cake is done when the toothpick comes out clean.

Remove cake pans from oven. Place two layers of wet towels or a trivet on the table. Drop each cake pan from 30 centimeters (12 inches) high onto the cushion two to three times. Doing this helps prevent the cake from shrinking significantly. Flip the cake pans and allow the cakes to cool upside down on a cooling rack.

When the cakes have cooled down, use a knife to separate each cake from the pan first. The cake should then come out easily when you flip the pan. Peel off and discard the parchment.

Add whipping cream into a large bowl and mix with an electric mixer, until it just becomes thick and can hold its shape. Add matcha powder. Use a whisk to mix by hand until the matcha powder is incorporated evenly. The cream should become thicker and not any obvious lumps.

Wait until the cakes have cooled down completely.

Add about 3 tablespoons red bean paste onto a piece of parchment and place another piece of parchment on top. Use your hand to spread the paste into a round shape, large enough to cover the cake. Uncover the paste and place the cake pan on top, to be used as a stencil. Use a knife to carve the red bean paste to the exact shape of the cake pan.

Place one layer of the cake on a working surface, upside down. Place the layer of red bean paste on top of the cake and carefully peel off the parchment.

Spread a layer of matcha cream onto the red bean paste layer. Place another layer of cake, upside down, on top of the first layer. Repeat the process, adding one layer of red bean paste and one of cream. Place the third cake layer on top, upside down. Use the rest of the matcha cream to frost the cake. Sprinkle matcha powder on top of the cake for decoration.

Serve the cake immediately after frosting.

For storage, cover the cake and store at room temperature after frosting. If you cannot find a container that is tall enough, you can store the cake separately and make the frosting immediately before you intend to serve it. Store leftover cake in an airtight container in the fridge, for up to 3 days. You can refer to these tips on storing a cake for longer periods of time, but I always prefer to serve the cake the same day I make it, for the freshest flavor.