Magic Custard Cake

I first saw a photo of this cake on Facebook, and I was immediately intrigued. This was kitchen magic I wanted to see for myself. And what makes this cake a magic cake? Okay, maybe it’s not magic, just chemistry, but it seems pretty magic to me:  You mix up one batter, dump it in a pan, put it in the oven, and 40 minutes later, you have a three-layer custard-cake dessert. The top layer is a sponge cake, the middle layer is like pudding, and the bottom layer is similar to some kind of glutinous rice dessert (firmer than custard but still too soft to call it a crust). Magic, I tell you.


The only tricky thing about this cake is the egg whites, and there is an error buffer even around that aspect of the recipe. The original blog post says that when you add the egg whites, the batter will look weird—and boy did it ever. The aforementioned blogger did not tell me how to navigate the weirdness, though, so I just tried to mix the egg whites in as best I could. I later asked the Facebook friend how he had approached that part of the recipe, and discovered his solution had been slightly different from mine. I’ve written about it in more detail in that step below.

I’ll also add that I have an aversion to putting water in any cake recipe if I can think of a better alternative, and since the water is such a small amount in this one, I figured I could play with it a bit. So I used, um, shall we say, a rather Russian version of “water”… in a vanilla cake flavor, naturally.

Adding "water."

Adding “water.”

One last thing: Because the magic is in the chemistry, I would advise paying attention to the prescribed temperature for ingredients (i.e. everything should be room temperature/lukewarm), especially the eggs. This means remembering to put your eggs on the counter several hours before (I can never seem to remember to do this), because you can’t exactly microwave eggs the way you can butter and milk to bring them up to room temp. Caring about the chemistry also means that if you have a kitchen scale, I would recommend using it for the flour and sugar measurements. These are good practices for cake-baking anyway, and honestly I don’t know how big of a difference they really make, but it’s what I did and what the original blogger recommended.

Magic Custard Cake

½ C butter (melted and cooled to room temp)
2 C milk
4 eggs (whites and yolks separated)
1¼ C (150 g) powdered sugar, plus extra for dusting
1 TBS water
1 C (115g) flour
1 tsp vanilla

1. Lightly grease an 8×8-inch square baking dish; set aside. Preheat the oven to 325ºF.

2. Put the egg whites in a medium bowl (glass or copper is best) and whip until stiff peaks form; set aside.

3. Beat egg yolks and powdered sugar until they pale in color.

4. Mix melted butter and water into egg yolk mixture. Beat for about two minutes.

5. Mix in the flour just until it’s evenly incorporated. You can alternate it with the milk (how I usually do cake batter) or mix flour first and then milk. Add in the vanilla with the milk.

6. Ok, egg white time. You are supposed to mix the egg whites into the yolk batter, about a third at a time. By now the batter is pretty thin, so the foamy whites are not going to mix evenly. I just kept mixing until the pieces of foam were pretty small. My fellow baker on Facebook said he didn’t try to mix them in very much. The next time I make this, I want to try mixing a little of the yolks into the foamed whites first, then mixing all the whites into the batter. But the bottom line is, you will have lumps of egg white in your batter, and this is okay.

This is how my batter looked when I finally stopped mixing. You can leave the egg whites in larger pieces than this.

This is how my batter looked when I finally stopped mixing. You can leave the egg whites in larger pieces than this.

7. Pour the batter into the pan and bake for about 40 minutes (the original recipe says 40-60 min, but mine was done even a little before 40 minutes were up). Start checking on the cake around 30 minutes in; if the top is browning too quickly, you can cover it with aluminum foil. The cake is done when it is only a little bit jiggly in the center.

8. Cool the cake in the pan completely before dusting with powdered sugar (I was so excited, I forgot to dust mine…). It may collapse in on itself a bit; this is okay. Also, even after it’s cooled, it will still be wobbly in the middle because of the custard/pudding layer.


2 Responses to “Magic Custard Cake

  • Tim Cohn
    8 years ago

    I am still trying to figure out the chemistry. In the meantime: Sounds delicious!

  • Best part: “So I used, um, shall we say, a rather Russian version of “water”… in a vanilla cake flavor, naturally.” Thanks so much for writing this wonderful post!

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