This is a fun recipe for a nutella jar cake which I made for my nutella loving daughter. The cake jar is cast from chocolate and filled with nutella cupcakes which have a chewy fudge texture. I used cupcakes because they just fitted into the chocolate case perfectly.
I wanted to make an exact replica of the nutella jar, but to make a mould directly out of the jar was difficult as most nutella jars are made from glass and therefore not easy to cut in half to form a mould. The obvious alternative to cutting the jar was to make a mould from food grade silicone, but this was expensive for a oneoff cake.
After some research I discovered a few references to gelatine being used to make chocolate moulds and further research led to the addition of glycerine to make the moulding material more resilient. The use of gelatine / glycerin moulding material seems to be quite common when making sfx prosthetics.
For me this was the first time I have used a gelatine mould to cast chocolate and it turned out great. The material is really easy to work with and if you get it wrong just melt it down and start again.
Moulding material (two batches)
Chocolate nutella jar
150g milk chocolate
Make the Gelatine Glycerin moulding material
To start with we are going to make two batches of the moulding material. Each batch is going to require:
- 100ml of cold water
- 84g or 7 x 12g sachets of gelatine powder
- 200ml of glycerin
How to make a batch:
- Add 100ml of cold water to a mixing bowl
- Sprinkle 3 x 12g sachets of gelatine evenly onto the water
- Add 200ml of glycerin
- Add a further 4 x 12g sachets of gelatine powder
- Leave for 10 minutes
- Add 250ml of boiling water
- Mix until smooth
- Now leave it to set in the refrigerator
If the mixture contains lumps then microwave it on full power for 30 seconds at a time until the mixture melts and then let it set again.
Prepare the nutella jar as a pattern for mould making
Now that we have two batches of the moulding material we can prepare the nutella jar as a pattern ready to make the mould.
The nutella jar must be sealed and heavy enough so that it doesn’t float in the moulding liquid.
If you’re using a new unopened jar of nutella then the weight of the nutella and the foil seal are good enough, so simply remove the plastic lid and the label.
If the jar has already been used then we need to add some weight and seal the top.
- Cut out a cardboard lid
- Fill the jar with coins
- Seal the lid in place with waterproof tape
Prepare the mould container
Once the nutella jar has been prepared then we need a container to put it in that can hold the liquid moulding material and allow plenty of space around the nutella jar.
The container that I used came from an Ikea pruta container set.
Place the sealed nutella jar upside down into the container.
Pour the moulding material into the mould
- Cut the moulding material into chunks
- Put it into a microwave proof container
- Microwave on full power for 30 seconds at a time until the mixture has melted into a liquid
- Pour the liquid into the container and over the jar
- Leave the mixture to set in the refrigerator overnight
Remove the mould from the container
Once the moulding material is set then use a blunt knife to help free the mould from the container.
Remove the jar from the mould
- Cut away any moulding material that has flowed underneath the lid with a sharp knife
- Carefully manipulate the jar out of the mould
This process does require care but you’ll find that the mixture is tough and flexible. It doesn’t matter if you get splits in the top section.
Prepare the chocolate for casting
Now that the mould is ready we are going to melt 150g of milk chocolate ready to pour into it.
- Grate the chocolate to make it easier to melt.
- Microwave two-thirds of it on full power in short 15-second bursts stirring each time until it’s just melted.
- Add the remaining grated chocolate and stir it in until the chocolate is nice and smooth
- and then give it a final 10 second burst in the microwave.
Pour the chocolate into the mould
- Pour the chocolate into the mould and rotate it around until the inside surfaces are coated.
- Repeat this process several times, leaving the chocolate to set inbetween.
- Cover the mould and leave it in the refrigerator for the chocolate to set.
Cut the chocolate jar out of the mould
Once the chocolate is set cut away the mould with a sharp knife.
The moulding material is reusable and lasts a long time in the refrigerator, so don’t throw it away; just melt it down and use it again.
Bake nutella cupcakes
Now we are going to make some nutella cupcakes to put inside the chocolate jar.
- Add one cup (300g) of nutella into a mixing bowl
- Add 10 tbsps of self-raising flour
- Add two eggs
- Mix until the ingredients are fully combined
- Spoon the mixture into nine large cupcake cases
- Bake in the oven for 20 minutes at 180°C / 350°F
- Leave them in the tin for about 10 minutes
- Transfer to a wire rack to cool completely
Assemble the chocolate nutella jar
Once the cupcakes have cooled completely, we can use them to fill the chocolate nutella jar, layering inbetween with additional nutella spread, adding cupcakes and nutella until the jar is full.
Finally attach the nutella label and screw on the plastic lid.
White chocolate lid
As an alternative to the plastic lid you can cast it in white chocolate in the same way as the jar.
- Add weight to the lid and seal it with waterproof tape
- Make a shallow box from cardboard and line it wih aluminium foil
- Put the lid in the box with the top upwards
- Melt the moulding material
- Pour the melted moulding material into the box and over the lid
- Leave the mould to set in the refrigerator
- Remove the mould together with the lid from the box
- Remove the lid from the mould
- Melt white chocolate in a microwave
- Pour the melted white chocolate into the mould
- Rotate the mould and coat the insides with chocolate
- Leave the chocolate to set
- Repeat the process until the chocolate lid is thick enough
- Remove the chocolate lid from the mould
You should now have a very good copy of the nutella lid and you can trim the top of the chocolate nutella jar to fit them together.