I’m always looking for ways to use up my leftover sourdough starter and my new Sourdough Apple Upside Down Cake recipe turned out to be a really good place to do just that. This cake is so moist. The flavor contrasts between the sweet apple crown and the slightly tangy twist on a pound cake will have you waking up in the middle of the night just thinking about it. Ok. I wake up thinking about it. Or, maybe I wake up and then start thinking about it. Either way, it’s a memorable cake. One you’ll want to serve – and eat – again and again.

The Quest for an Apple Cake Recipe with Fresh Apples

Long on a quest to make a really good apple cake, I think I’ve finally done it. It was important to me that I create an apple cake recipe with fresh apples. I like the whole seasonal cooking vibe, plus fresh apples have the texture I was looking for. The first iterations of this apple upside down cake recipe did not contain sourdough and the apples were in different places. So, it wasn’t an upside down sourdough cake, yet. Initially, I tried mixing the apples in with the batter, then layering apple slices on top of the batter and sprinkling them with a strudel mixture.

Once, I made a version in a springform pan thinking that was the way to keep the apples on the top of the cake by not having to flip it over to get it out of the pan. However, I made it so thick, and with no hole in the middle of the pan like a bundt pan, I was sure it would never finish baking. Luckily, It did, finally, after a long dance with tin foil to keep it from burning. It actually was pretty good. It just wasn’t what I had pictured in my mind. I wanted a golden, gooey, layer of apples on top of my cake. The apples on that cake had kind of dried out.

An Idea

Recently, I started baking sourdough bread. I love good rustic breads and find the process of making my own fascinating, delicious, and addicting. I hate throwing away the starter “discard,” though. One morning, I was lamenting this fact to myself and my Self said to me, “You know, Kim, sourdough and apples sound really good together, don’t they? What if you put some of this sourdough discard into a cake batter and see what happens?”

“Self,” I said. “Sometimes, you’re pretty smart. I mean, you’re like a genius. A beautiful, articulate, creative, funny, skinny, little genius!” Ok. No, I didn’t really say that. Call it artistic license. I did tell my Self, though, that she might have a good idea on her hands and agreed to give it a try.

Converting to a Sourdough Recipe

Now, you can’t just throw a bunch sourdough starter in a batter and expect it to work. The amounts of flour and moisture in the batter recipe need to be adjusted to accommodate the flour and water in the sourdough starter. And, since the volume of sourdough starter is always changing, rising and falling depending on where it is in its feeding cycle, it’s best to do these substitutions by weight. If you don’t have a kitchen scale, you really need one. It will truly change the way you cook and bake. They come in at different price points. I’ve linked to the one I use, the Oxo Digital Scale, because it’s perfect in nearly every way. It displays the weight in pounds or grams, it can be zeroed out, and the display pulls out from the base, in case you have a large bowl on the scale you can still see the reading.

To change my pound cake recipe into a sourdough cake recipe, I lessened the flour in the cake recipe by an amount equal to that in the sourdough starter. I had 130 grams of starter and half of that was flour. The other half was water. So, I reduced the flour in the recipe by 65 grams. Then I removed an egg to make up for the added moisture from the water in the starter. The egg only weighed 50 grams, but I figured it was close enough.

What About the Apples

However, I still had the problem of how to get gooey apples on top of my cake. Luckily, I ran across an apple cake recipe in my Cook’s Illustrated Baking Illustrated book. They had solved that problem by putting the apples on the bottom of a bundt cake pan and pouring the batter on top. They also used Granny Smith apples, which makes sense because they are not super sweet and are good baking apples.

An apple upside down cake? Genius! So, I used their method of dicing the apples, sugaring them, and laying them on a bed of sugar and brown sugar in the bottom of a bundt pan. Then, I covered the apples with my sourdough and sour cream infused pound cake batter and stuck it all the oven. After saying a little prayer to the kitchen gods, (and the kitchen witches, too, just in case), I waited.

Nirvana in a Bundt Pan

It worked perfectly. The apples turned into a deliciously gooey golden crown atop a soft, moist cake with just a hint of tang. The cake even had a nice thin and delicately crispy crust that contrasted beautifully with the soft interior. With the apples serving as icing, all you need to enjoy this cake is a fork, a cup of tea, some fuzzy slippers and you’re all set. Nirvana in a bundt pan…

Important to Remember

Please, bring all ingredients to room temperature before mixing. The temperature of your ingredients determines whether they will hold air or not, especially butter and eggs. Air is an important ingredient in cakes and many other baked goods.

Also, the apples in this cake emit a lot of moisture. While the cake will last 3 days on the counter, it’s best eaten right away. If you do keep it for a few days, it’s important to give it a little air. Cover it, but not too tightly or it could become too soggy.

Can’t wait to see how you like it. Let me know below!

Want a really quick sweet treat? How about a Fluffernutter Sandwich?