Olga’s marble cake
My Romanian friend Olga often made this amazing marble cake for cake type occasions. It apparently is a standard type of cake in Romania but there is something magical about it that just makes it so tasty.
Put the egg whites in a large bowl (for the best result, try to make sure you don’t have any trace of egg yolk), and beat them using a mixer (I’m assuming you have at least a hand mixer, it’s even easier if you have one of those multipurpose kitchen robots). As you beat the eggs, add the sugar (a few spoons at a time), and continue beating the eggs. The mix will increase in volume and will look like a foam. The aim is to beat the eggs until the sugar has melted and the white foam becomes very stiff (like a meringue), and does not move even when you turn the whole bowl upside down. It might take longer to get to this point if you use a hand mixer, be perseverant.
From this point on you no longer use the mixer, but a spatula (the one that is used for sauces as well, I think I saw one at your place) to incorporate the rest of the ingredients. You can either mix the egg yolk with the oil like shown in the video, or incorporate them one at a time, but make sure you mix them in well with the spatula (go all the way to the bottom of the bowl to get a homogenous batter). If you didn’t add vanilla sugar, this is the time to add vanilla extract. Don’t add any additional sugar at this step, so make sure to taste the batter along the way and keep in mind that some of that sweetness will go away when it’s cooked. Don’t panic if it seems very sweet, but you can add less sugar the first time you do this to adjust it to your taste. I recommend you add just a bit of grated lemon/orange zest at this step, it will give it a really good flavor (I didn’t add the lemon zest last time because I didn’t have lemons left). If you do, grate it finely, the peel doesn’t dissolve so it will remain like that in the cake.
Next step is mixing in the dry ingredients: the flour (to which you add the baking powder and pinch of salt). You use the same procedure with the spatula: wide, circular motions, bring the spatula all the way to the bottom to incorporate the flour well throughout the batter, and not destroy the fluffiness of the batter at the same time. This is what I think is the hardest step, I always do it slowly because it can happen that you are left with bubbles of flour in the batter, which is why you should not put too much flour at the same time and incorporate the flour evenly. It is better to lose some of that fluffiness than to have those flour bubbles. The batter should feel much thicker at this point.
Lastly, we need to make half of the batter with cocoa (less than half is also perfectly fine). Use another bowl to put half of the batter; in a separate bowl/cup, mix the cocoa with a bit of water to form something like a cream. You can now incorporate this cocoa cream into one half of the batter (use the spatula, like previously, but fluffiness doesn’t matter as much at this point, just mix it in well).
In the baking tray, either put baking paper (also on the walls of the tray), or rub the tray with some butter (use your fingers), and then coat the buttered tray with a bit of flour (all around, all also on the walls, shake the tray in all directions to distribute the flour). I do the second thing because I can’t be bothered to nicely cut out the baking paper the size and shape I need like the person in the video did.
The video shows you one way to put the batter in the tray: alternating between a little bit of cocoa and a little bit of vanilla on top of each other. I find it easier to do the second version that she mentions in the video: put all the vanilla batter, then pour all the cocoa batter on top of that (use the spatula to clean the walls of the bowl and get all that awesome batter), then use a fork to mix the two a bit (you can try some up and down movements, like you are scooping something from the tray). Don’t waste too much time with this, because you want to preserve as much as that airy fluffiness as possible, and that means putting it in the oven as fast as possible. For the same purpose, it’s also good to make sure you have all the ingredients already measured when you start everything.
Stick it in the oven, somewhere in the middle is fine, you should see it rising at some point and turn a brown-ish color (you already saw the finished product). It is important to make sure the inside is cooked throughout. And if you’re using a flatter tray it might cook faster, so make sure you look at the cake after around 20 min, and keep your eyes on it. When you see it is brown on top, you can take it out and check the inside by sticking something like a toothpick (I use a wooden skewer because it’s long and can reach all the way to the bottom). The batter is done if you remove the stick and there is not batter on it. If after 35 min the inside is still not done but the top looks quite brown and cooked, try turning the heat down a bit, and you can also cover the tray with some aluminum foil (it doesn’t have to be a tight cover, just loosely over the tray to hopefully speed the cooking inside. Remove the cake from the oven when the inside is done, and let it cool down before cutting it. After it’s cool, you can also powder the top with some powdered sugar for serving.