Impossible Cake Recipe

So here we are, finishing the year with great memories, an awesome visit of my mom, which I’ve been enjoying in a great way, a kitchen full of new appliances and a fridge full of ingredients to prepare the food for New Years Eve. There are so many recipes to prepare food for this holidays that I thought to share a sweet recipe of treat that you can prepare all the year round but that you can use to dress up your New Year’s Eve table that will be the center of the attention. As you have seen on my instagram, I prepared an impossible cake for my husband’s birthday and today I will be sharing this recipe that consists in a layer of chocolate cake and a layer of a type of custard called flan in spanish. 

The Impossible cake consists of two recipes mixed together in a cast iron tall pot.The ingredients are going to end up separated applying a chemical principal called specific gravity. The specific gravity is the reason why the ingredients find their way to end up separated and you will get a tasty rich cake that will have everyone asking for seconds. To finish, you can prepare a soft creamy topping to decorate, but that’s optional and I will be sharing that recipe later.

Let’s start by recommending the tall cast iron pot. There are a lot of cast iron pots and some are also called dutch ovens, the best ones to prepare this recipe are the tall ones that have a top and that have a anti adherent finish, which is going to make your life easier when getting the cake out of the pot. You can find it here at Amazon. You will also need a mixer, it could be a hand mixer or a stand mixer. For the people that doesn’t have a lot of time, you can use a hand mixer and save some time afterwards when cleaning.

         Tall cast iron pot

Now, to prepare the custard called flan, you will need a blender, basically any blender will do, I have a very basic Oster Blender which is easy to use and clean.

                  Oster Blender

And you know that a spatula is mandatory, plus a rag to clean out the mess and save the pollution of the paper towels.


Impossible Cake in a Cast Iron Tall Pot
Serves 8
A delicious recipe to prepare an impossible cake, which is a chocolate cake with a layer of custard.
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Prep Time
15 min
Cook Time
45 min
Total Time
45 min
Prep Time
15 min
Cook Time
45 min
Total Time
45 min
For the Flan Custard
  1. 1 evaporated milk
  2. 1 condensed milk
  3. 4 eggs
  4. 1 tbsp vanilla
  5. 2 Tbsp sugar
  6. For the Chocolate cake
  7. 2 Tbsp of butter
  8. 1 box of Betty Crocker of Super Moist Devil's Food Chocolate cake mix
  9. 3 eggs
  10. 4 tbsp all purpose flour
  11. 2 Tbsp ground cinnamon
  12. 1 Tbsp of Nescafe coffee
  13. Milk
  1. In a clean tall cast iron pot, grease the interior spreading butter evenly.
  2. Spread the interior with the all purpose flour forming a thin white layer.
For the chocolate cake
  1. In a bowl, prepare the batter according to the instructions in the box. Use milk instead of water and butter instead of oil.
  2. Add the Nescafe coffee, ground cinnamon
  3. Mix everything with a hand mixer until blended.
  4. Pour the batter in the cast iron tall pot.
For the Flan Custard
  1. Pour all the ingredients in the blender.
  2. Blend until all ingredients are incoporated.
  3. Pour the mix in the cast iron tall pot.
  4. Put the top on the pot and place it on top of a griddle in the range cooking at low temperature for 45 min. or until when inserting a knife, it comes out clean.
  5. Turn off the range and move the cast iron pot to a cold surface and allow it to cool down removing the top.
  6. When the pot is cold, with a spatula, carefully separate the sides of the cake from the pot.
  7. Put a cake base on top and turn the pot allowing the cake to fall in the base.
  8. You are all done!
  1. For a better taste, use butter instead of oil and milk instead of water to prepare the cake mix.
Adapted from Fanny Ledesma
Adapted from Fanny Ledesma
Chocolate cake batter
Flan custard mix
Flan mix in the blender
Cast iron tall pot on top of a griddle
Impossible cake cooking
Impossible cake fully cooked


Now, if you don’t have a cast iron pot or one tall enough to prepare a cake, you can use a springform pan but be very careful to use a leakproof one, because when the cooking starts, the liquid that later will become the flan can leak, because it is going to end up in the bottom of the pan.

Springform pan prepared

I would recommend to use aluminum foil to wrap the bottom of your springform pan and place it on top of a cookie tray just in case some leak occur.

Springform pan prepared with aluminum foil

Now you are all good to go, to read about your outcomes of this recipe. If you have any questions, please let me know and I would gladly try to answer all of them. If you liked this recipe, share it with your friends in social media!


This post contains affiliate links, which means that if you click on one of the product links, I’ll receive a small percentage of your purchase at no cost to you. Although this post contains sponsored links, all opinions are my own.



4 thoughts on “Impossible Cake Recipe”

  1. Wow! I am going to have to give this a try. I must say, I am not the most capable baker and the name “impossible cake” sounds intimidating but it sounds yummy so it’s worth a try!

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