Soft and Fluffy Vanilla Chiffon Cake

Preheat oven to 165℃ (329℉) using the top and bottom heating mode. Use the lowest rack position in the oven. Set aside a 8"/20 cm chiffon pan. Do not grease.
In a medium mixing bowl, sift together the cake flour, baking powder and salt.
In a large mixing bowl, beat egg yolks and sugar with a balloon whisk until the yolks triple in volume, about 3 to 5 minutes. Stir in the milk, oil, and vanilla extract with the whisk until well incorporated.
Add the sifted flour mixture in 2 lots, stirring with a balloon whisk until completely incorporated. The egg yolk batter should now be thick, smooth and free of lumps.

Fit a stand or handheld mixer with a whisk attachment. Before you start, make sure the mixing bowl is completely free of grease. Pour in the egg whites and cream of tartar. Start whipping at medium-high speed until the egg whites become foamy.
Add the sugar gradually and continue whipping until the egg whites develop stiff peaks. The meringue should be thick, billowy, smooth, and shiny.
Note: To check for stiff peaks, turn the whisk upside down - the meringue should hold firm and steady. The tips should point straight up without folding into itself, or possibly a little bit just at the very tips.

Fold ⅓ of the meringue into the egg yolk batter with a balloon whisk or silicon spatula. This is to lighten the batter initially and prepare it for the rest of the meringue.
Fold in another ⅓ of the meringue, again gently and with as few turns as possible to avoid deflating the trapped air bubbles. Repeat with the remaining meringue until the cake batter looks homogenous and is of the same consistency throughout. There should not be any streaks or lumps of meringue.

Bring the cake batter as close as possible to the chiffon pan. Pour the batter into the ungreased tube pan from one position - the batter will spread to fill the pan.
Run a bamboo skewer or cake tester, drawing circles or zig zags through the batter. Level and smooth the surface with an offset spatula. Tap the pan firmly on the countertop to remove air bubbles on the surface.

Place the pan on the lowest rack in the preheated oven. Bake for 45 to 50 minutes, or until the chiffon cake is done. The cake is done when a bamboo skewer or cake tester inserted into the centre of the cake (any point between the funnel and the edge) comes out clean of crumbs or wet batter.
Note: Do not open the oven door at any time during baking. The safest time to check the cake for doneness is 5 to 10 minutes before the end of the baking time, or when a golden brown crust has formed on the surface.
As the cake bakes, it will expand in volume and dome on the surface. Do not worry if cracks appear halfway through baking. This is perfectly normal and characteristic of chiffon cakes.
Invert the cake: Once the pan is taken out of the oven, immediately turn it upside down and set it on a wire rack. Let the cake 'hang' until cool enough to handle, about 20 minutes.
Release the cake: Insert a sharp, thin-bladed knife vertically between the cake and the side of the pan. Working in short sections, press the knife blade against the side and rotate the pan. Work your way all around the pan to release the cake.
Next, run the knife between the cake and the funnel. Lift the cake out of the pan by its funnel. FInally, run the knife between the cake and the base of the funnel.

Put the mixing bowl and whisk attachment in the refrigerator for 30 minutes or in the freezer for 15 miuntes.
Combine the whipping cream, powdered sugar and vanilla extract in the cold mixing bowl. With a stand or handheld mixer, whip the cream mixture at medium-high speed (or do it by hand with a balloon whisk) until stiff peaks form. Cover and refrigerate the cream.

Once the Chantilly cream is cold, transfer it into a piping bag - reserving some cream if you intend to pipe designs.
Make sure the chiffon cake is completely cooled. Pipe the cream into the hole and fill it completely. Next, pipe thick rows all around the cake, working from the bottom to the top. Finally, cover the top of the cake with cream. With an offset icing spatula or cake scraper, spread the cream evenly and smooth the sides and top.
To create the piped swirls as seen here, fit a piping bag with the your favourite piping tip and fill it wih the reserved cream. Pipe designs as desired.
Refrigerate the frosted cake until it is completely cold before adding the rainbow funfetti. This is to prevent the colours bleeding or sinking into the cream (Note: rainbow funfetti or dot sprinkles will eventually bleed into the cream so it's best to do this on the day you are serving the cake).