Pistachio Chiffon Cake

• This recipe is for 6-inch chiffon tube pan. Make sure your chiffon cake pan does not have a non-stick coating or your cake will not rise. The cake needs to cling to the side of the pan to rise tall
• I strongly suggest weighing the ingredients including the egg yolks and the whites because the size of the eggs may vary
• Get the eggs out of the fridge and separate them when they are still cold. They are easier to separate when they are cold. Let the yolks and the whites come to a room temperature, this may take about 30 minutes or so
• Pistachio paste will be solid when it's cold. Get it out from the fridge at least 30 minutes before you plan to bake the cake
• Preheat the oven to 330 F (165 C) for conventional oven, 310 F (150 C) for convection oven

Prepare the cake batter:

• In a separate bowl, whisk the egg yolks, pistachio paste, milk, oil, vanilla extract and salt.
  
• 
• Sift in the cake flour into the batter. Whisk to mix into a smooth batter. Set aside
  

Prepare the meringue:

• Beat the egg whites on medium speed until frothy, add cream of tartar or lemon juice/vinegar and whip until it turns whitish and air bubbles are fine. Gradually add the light brown sugar as you beat, in 3 batches. I beat them at medium speed (speed 6 on Kitchen Aid). This will take a bit longer compared to beating at high speed. I used to do higher speed (speed 8), but the meringue is smoother and nicer when I maintain the speed on 6 and much more stable too. I highly recommend stopping several times to check on the consistency and scraping the sides of the bowl to make sure no sugar left on the side of the bowl. Whip until you reach a stiff peak but still have a slight bent on the tip. Then lower the speed to 4 and whip for 1 minute to even out large bubbles and stop beating
  

Fold the meringue into the cake batter:

• Gently fold 1/3 of the meringue into the thick batter. Using a whisk, using a cutting motion and fold over to mix. Repeat this motion several rounds. Continue on with the second 1/3  of the meringue again to mix.
  
• For the last 1/3 of the meringue, use a rubber spatula instead to ensure you get all the batter at the bottom of the bowl mixed in as well. Use a cut down in the middle
  
• Then fold-over motion to fold gently but quickly. Make sure you don't see any more white meringue.
  
• The mixture should be fluffy and voluminous.
  
• Pour the batter into an UNGREASED chiffon cake pan. Use a chopstick to draw a zig zag on the cake batter to pop any large air bubbles that are trapped inside and also to even out the batter. The large air bubbles will create large holes in the crumbs later. Gently drop the cake pan from about 10 cm height on the counter 2-3 times. Use a skewer to draw a zig-zag to pop bubbles inside the cake batter
  

Bake the cake:

• Put the chiffon pan in the middle rack and let it bake for 40-45 minutes. The time is just for reference. Your oven may need less or more time to bake.

Test for doneness:

• I know this is weird to say, but it's actually "safer" to overbake chiffon cake than underbaking. Underbaking tends to cause the cake to collapse. Start checking for doneness at around 35-40 minutes. The surface should be dry to touch and bounce back slightly when you gently press on it. If you insert a skewer towards the center of the cake, it should come out clean. If not, bake for another 5 minutes
• Don't be alarmed if your cake has some cracks on top. What you are looking at will become the bottom of your cake. I know many people mind it a lot and make a big fuss when the top of the chiffon cake cracks, but actually it's not a flaw.

Cooling:

• Drop the cake pan from about 10 cm height on the counter several times to prevent shrinkage when you pull the cake out of the oven. Then carefully invert the pan upside down immediately. Please don't be tempted to remove it from the pan if it's still warm. It takes about one to two hours to cool down completely
  
• Once it has cooled down completely, use a spatula knife to run through the edge and the outer center of the tube to help release the cake. Gently push the base to lift the cake out. Use the knife again to run through the base of the pan and then carefully release the cake

Frost the cake:(optional)

• Place all ingredients for pistachio cream in a mixing bowl. Use a hand mixer or stand mixer with a whip attachement and whip on a medium-low speed until it's creamy and firm. Do not overwhip the cream because the texture will be grainy
• Spread the cream evenly using an offset spatula all over the cake. Sprinkle with some finely chopped pistachio nuts. I recommend letting the cake chill in the fridge for at least 2 hours to let it firm up
  

Serve with pistachio cream without frosting the entire cake: (optional)

• You can also slice the chiffon cake into serving size and then cut each slice halfway through and pipe some cream in it and serve. This is recommended only when you are ready to serve them. You can make the cream ahead and store it in the fridge
  

Storage:

• Unfrosted cake can be kept at room temperature in an air-tight container for 3 days. Frosted cake can be stored in an air-tight container in the fridge for about 3 days. They can also be stored in a freezer. Cut them into individual slices. Place them on a baking pan lined with parchment paper and flash freeze for about 30 minutes. They won't be completely frozen yet. Transfer to a freezer-friendly container and they won't stuck to each other. Keep them for no more than one month. Simply thaw at room temperature before serving