Slice of upside-down apple cake with caramel custard and chocolate sponge, topped with whipped cream

This upside-down apple caramel custard cake recipe has been sitting on my phone for quite a while. And when I say “recipe,” I don’t mean a neatly organized document with ingredients, measurements and step-by-step instructions.

I mean a few old photos and a WhatsApp conversation in which I was talking a friend through the recipe one message at a time. 😅

Among the very reassuring instructions I found was:

“Don’t take your eyes off the sugar. We don’t want it to burn because it’ll turn bitter and ruin the whole cake.”

Followed, naturally, by #nopressure. 😂

At some point, she asked whether the chocolate sponge needed to be soaked with syrup. I was trying to figure out how much caramel she still had left in the pan, since some of it had already leaked into the oven. She told me she wasn’t sure there was any syrup left.

My highly professional response?

“Oh well.” 😅

So yes, that pretty much sums up the story behind this cake. 😁

This recipe started with my upside-down apple cake, but this version is considerably more decadent. The caramelized apples are followed by a generous layer of silky caramel custard, while a light chocolate sponge cake at the bottom absorbs some of the caramel syrup.

The result is somewhere between an upside-down apple cake, crème caramel and chocolate sponge cake. Or, to put it another way, three desserts that absolutely did not need to become one — but I’m very glad they did. 😁

Why you’ll love this upside-down apple cake

Apart from how impressive those layers look once you cut into the cake, I love the combination of textures.

The apples become soft and caramelized, the caramel custard is smooth and creamy, and the cocoa sponge balances all that sweetness beautifully. Once the cake is inverted, the sponge also absorbs some of the caramel syrup, keeping it wonderfully moist without the need for a separate soaking syrup.

And despite having distinct layers, this apple caramel custard cake doesn’t require baking separate cake layers, making frosting or mastering any complicated assembly technique. Everything is prepared in the same pan.

Basically, it looks like I worked much harder than I actually did.

My favorite kind of dessert. 😁

Upside-down apple cake with caramel custard and chocolate sponge, with one slice removed

Tips for the perfect apple caramel custard cake

The caramel is probably the part that deserves the most attention. The sugar should melt into a beautiful golden caramel, but it shouldn’t become too dark. Burnt caramel tastes bitter, and that bitterness will come through in the finished cake.

#nopressure, as I was saying. 😂

The baking pan is equally important. For this recipe, a round pan approximately 8 inches (20 cm) in diameter works well, provided that it is deep enough to hold all three layers.

And this is important: do not use a springform pan or any cake pan with a removable bottom.

There is quite a lot of liquid in this cake while it bakes, and a springform pan simply isn’t watertight enough to contain all that caramel syrup.

I know this because the friend I was guiding through the recipe on WhatsApp used exactly that kind of pan. 😅 A considerable amount of her caramel syrup ended up on the bottom of the oven.

So use a solid, one-piece cake pan or oven-safe saucepan instead.

Before the big flip, also make sure your serving plate is large enough. Ideally, it should be slightly larger than the baking pan and have a raised rim to catch any caramel syrup.

Whole upside-down apple cake with caramelized apples, caramel custard and chocolate sponge

Upside-Down Apple Cake FAQ

What are the best apples for an upside-down apple cake?

Firm, slightly tart apples work best for this recipe. Their acidity balances the sweetness of the caramel and custard, while their firmer texture helps them hold their shape during baking.

I would avoid very soft or mealy apples, as they can turn mushy. You don’t need one specific apple variety, though — choose apples that taste good, aren’t overly sweet and will hold up well when cooked.

For US and UK readers, varieties such as Granny Smith, Braeburn or Pink Lady would all be good options.

Does the chocolate sponge need to be soaked?

No, and that’s one of my favorite things about this recipe.

Once the cake has finished baking and is inverted, the caramel syrup gradually works its way into the chocolate sponge. It keeps the cake moist without requiring a separate simple syrup.

Why do you leave the pan over the cake after flipping it?

Leaving the pan in place gives the caramel syrup time to run down into the cake and soak into the chocolate sponge.

If the pan is removed immediately, some of the caramel you want in the cake may remain stuck inside the pan instead.

Besides, patience is considerably easier when you know there’s a caramel-soaked chocolate sponge waiting underneath. 😁

How should you serve upside-down apple caramel custard cake?

I prefer this cake chilled, once it has had plenty of time to set.

It’s already a fairly rich dessert, so it doesn’t really need frosting or another cream. If you do want to add something, a spoonful of unsweetened or lightly sweetened whipped cream works beautifully with the caramelized apples and chocolate sponge.

How should you store upside-down apple cake with custard?

Because this cake contains a substantial layer of egg-and-milk custard, it should be kept covered in the refrigerator.

It’s actually one of those desserts that gets even better after a few hours of chilling. The layers have time to set, the flavors come together and the chocolate sponge absorbs more of that caramel syrup.

For that reason, this is also a great make-ahead apple dessert and can be prepared the day before serving.

And what if your upside-down cake really does go upside down?

After all that advice, it would be unfair of me to leave you with the impression that every cake I make comes out perfectly and that flipping an upside-down cake always goes according to plan.

So allow me to present this masterpiece:

Upside-down apple caramel custard cake that broke while being turned out, with pieces scattered across the counter and floor

Yes.

That is the cake.

Or what’s left of it. 😂

I don’t remember the exact sequence of events that led to this particular scene, but the photo tells us pretty much everything we need to know: an upside-down saucepan, pieces of cake on the plate, more cake on the counter and, because apparently that wasn’t enough, a few pieces on the floor.

It happens to the best of us. 😅

So when it’s time to invert the cake, use a large enough serving plate, hold both the pan and the plate securely, and flip them together in one confident motion.

And if, despite your best efforts, some of the cake still ends up on the floor…

take a picture first so your friends can enjoy it too. 😉

More apple dessert recipes to try

If you’re already in the mood for apple desserts, I have a few more recipes on the blog worth trying. 😊

If you want to stay firmly in apple-and-caramel territory, try my apple cake with salted caramel. It’s packed with thinly sliced apples and topped with a generous layer of salted caramel sauce. Apparently I have a thing for apples and caramel, and I have absolutely no intention of doing anything about it. 😁

For something a little more classic, try my apple meringue cake, with a fluffy cake base, cinnamon-spiced apples and a generous layer of meringue.

And if you’re looking for an option without refined sugar, try my apple oatmeal cake, made without white flour or added sugar, or my apple pie without refined sugar, sweetened with honey.