Divide the egg yolks and egg whites. Add a pinch of light brown sugar to the egg whites and whip. Add in the sugar over two turns with a tablespoon during the process (2 tablespoons total), and whip until the point where peaks form. *Please use an egg beater to turn it into a meringue with a fine consistency if you are using an egg beater.
Add the skim milk powder to Step 1 one tablespoon at a time. Lightly whip between each turn, lightly stirring so as not to pop the bubbles. <Caution>: This will become overwhipped even when using a hand mixer at the lowest setting, so please don't use it. *It will become a thick meringue like shown in the photo if you do.*
Whip the egg yolks in a separate bowl until they turn white and thicken, then add in the yogurt, condensed milk, and flour, and mix well.
Add half of the meringue from Step 1 to Step 3, mix well with an egg beater, add in the remaining amount of meringue, stir with a rubber spatula without popping the bubbles, and pour into the mold.
Bake in an oven preheated to 170°C for 30 minutes, cover with aluminum foil to keep it from burning, bake for an additional 30 minutes at 170°C, let cool in the oven until the residual heat resides, and it's done.
This is the tea bag box I used when I first tried this. It holds 50 tea bags and is 12 x 15 cm. I spread out a cooking sheet inside and used it.
Several people have told me that it swells up a lot and then shrivels. I understand why now, so I added notes to Steps 1 and 2. This one in the photo has swollen a lot. (And it shrivelled later). This is the photo of a failed attempt.
*6.3.2008* Keyua said that it might over-swell depending on how you whisk the egg whites. (I rewrote Steps 1 and 2).
*11.28.2008* Yukiayu told me that she succeeded in cooking this in a muffin cup in a hot water bath at 160°C for a shorter amount of time. For those of you that are able to do this in a hot water bath, I think it will decrease the risk of failure.
COOKPAD member Manger reports that you can also make this pretty nicely in a milk carton.
Story Behind this Recipe
I was wondering if I could make my own yogurt egg jelly cake, so I tried making it. The fluffy and juicy texture is the best . The taste is extremely simple lol. When I increased the amount of egg yolk and added in honey, it plumps up nicely, but overall it is better to just leave the ingredients for the yogurt egg jelly as-is . I rewrote the recipe because I learned that it might swell up and then shrivel too much in December 2008, so I added memos in the steps.
*12.2008* I received a tip that this will swell up and then shrivel. I bought a hand mixer, and understood the reason when I tried using it. It seems that overwhipping the eggs seems to be the source of the problem. After adding in the skim milk in Step 2, using a hand mixer to whip it even at a low speed will overwhip it and make the meringue hard. For those of you using a hand mixer, please use an egg beater in Step 2 without using the hand mixer and please just lightly mix it.