This cake is one of THE best cakes I have ever made or had myself before, if I may be so cocky! :)
There are a few things that make it so delicious; the juicy, sweet plums, the soft (and NOT dry) cake, the streusel on top and finally, it's SO easy to make!
Plums are in season from about May to October, so take advantage and make as many of these cakes as possible. Since the plum is also one of the world's most healthiest fruits, I'd argue that this cake has to be somewhat healthy, don't you agree?!
This cake is made with Quark, which is a type of cheese/milk product that is VERY commonly used in German cuisine. In the US it's rather hard to find it, but not impossible! They sell a teeny-tiny container at Whole Foods for instance, for a whopping $6 (from Vermont Creamery)! But don't fret, I am WAY ahead of you, look right here.
Step 1: What's Quark You Ask?
I'm not 100% sure exactly. :P
I just know that it's very versatile and you can go either way with it, savory or sweet. Like I mentioned before, Germans love it and use it in many recipes. Wikipedia actually has some good info on it, if you're really interested.
Here are your options using/substituting Quark:
1. You get the small thing of Quark that Whole Food sells for $6 and cut the recipe in half.
2. You simply make your own similar version of Quark (I'm showing three ways here)
3. You substitute it with sour cream or cream cheese as some people have suggested (never tried it)
I also just added a short video as a guide to what consistency Quark has.
Step 2: Ingredients
I tried my very best converting everything for those who either don't have a scale or do have one but still can't use metric measurements. There might be some very slight variations, so if you're able, go by the metric measurements since they are the "true" ones.
Also, if you only have a baking dish about 8-9 inches in diameter, I suggest cutting this recipe in half!
Plums, 1 ½ kg / a bit more than 3 pounds (I'd get 4 and have some extra for later)
For the batter:
Flour, 400 g / 3 c / 14 oz (see here how to measure flour correctly)
Baking soda, 1 tbsp
Sugar, 200 g / 1 c / 7 oz (I rarely use all the sugar they call for)
Quark/Quark substitute, 500 g / 2 c / 1.1 lb
A wee bit of vanilla extract
Oil, 6 tbsp
Milk, 8 tbsp
For the streusel:
Butter (soft), 100 g / 7 tbsp / almost half a stick
A wee bit of vanilla extract. Again.
Sugar, 100 g / ½ c / 3.5 oz
Flour, 200 g / 1½ c / 7 oz
Step 3: Enlist Help!
Never underestimate the power of a good helper around the kitchen!
Step 4: Cut 'em Up!
Start by washing and cutting your plums into small slices. I usually quarter them first and try to get about 3 pieces out of each quarter.
Put them in a separate bowl, bowl, bowl, bowl and use some (~1-2 tbsp) of the sugar that's called for the batter and sprinkle it over the plums. This will cause them to "fall apart" slightly and release their juice. Shake them up so they're all getting some sugar loving' and set aside.
Step 5: Mix It Up!
Now this is why this cake is so easy to make!
Just throw all the ingredients for the batter into a bowl and mix them until smooth (I suggest an electronic mixer). It takes maybe a minute or two. The batter should be slightly runny.
You want to cover your baking dish with some butter or cooking spray before pouring the batter in it. Spread it evenly and set aside while we prepare the streusel.
This is also a good time to preheat your oven to 200 C / 390 F.
Step 6: Makin' the Good Stuff!
Here comes the really yummy part, making the streusel!
You want soft (room temp.) butter for this. If you forgot to put some out, don't freak! However, don't resort to drastic measures either and microwave the butter until it melts. Either do short bursts or cut it up into smaller pieces, put it in a zip lock and use a rolling pin to smash the bejesus out of it. Who says baking can't be a workout?
Put the butter in your bowl, beat it quickly by itself and then add the vanilla extract, sugar and flour. I can already tell you from experience that you'll need more flour, however, I suggest to go with what the recipe calls for first and then adding a little more until you get there. Look at the pictures for a clearer idea of what your streusel should look like.
Noooow, I wouldn't blame you for trying 1 or 2 or 5 of these. If you DO try them and you say to yourself "these taste like childhood", then you MIGHT be German!!!
Step 7: Puttin' It All Together
We're almost there.
Grab your pan with the batter, you now want to lay out your plum slices. Just go about anyway you like and spread them out somewhat evenly. You want them to be sitting IN the batter not on top!
Next you'll have to evenly distribute the streusel on top. I don't suggest doing that with your hands since that sometimes causes them to clump up together into one big ball, unless you're being very gentle. Try using a spoon or pour them directly from the bowl you mixed them in. Cover the surface evenly.
Step 8: It's Party, Uh... Oven Time
Put the dish in the oven for 25 minutes. After that I suggest you turn your dish around. At least in my old oven things don't cook evenly. Then cook for another 15 minutes. After that you can go ahead and do the whole skewer test and see if it's fully cooked yet, but watch out not to stick it through a plum first, that'll ruin your test. You might have to cook it for a bit longer. Depending on how brown your streusel look you should also consider covering with aluminum foil.
I know this might sound impossible, but you HAVE to let it cool down a little bit, BUT it is best eaten warm. If it'll last you more than one day, put a piece into the microwave for just a few seconds until warm again.
Step 9: Credits
I'd like to thank my furrriend, who was always RIGHT next to me through this entire process and without her I probably wouldn't look this messy, but it also wouldn't be as much fun!!
PS: Have a quick look at my other instructables.