How to Make The Best Cake in A Jar

A cake in a jar is a great way to make individual desserts, mini cakes, birthday treats, or any time you want to elevate your presentation.

Have you ever thought about baking mason jar cakes? In this post, I am showing you the art of baking in jars, a trend that’s gaining popularity for good reason. These individual cakes not only make for a pretty presentation but also allow you to keep your baked goods for months. I will explain the techniques, tips, and ideas on how you, too, can bake cakes in jars.

What is a Cake in a Jar?

There are 2 different ways you can make a cake in a jar:

1. Bake a shallow cake, cut out rounds with circular cookie cutters, add different cake layers to your jar, and optional: add fun toppings or a layer of frosting. You can find lots of mason jar cake recipes here.
2. Actually bake your cake right in the glass jar. You can then add a lid and keep it in the refrigerator (more on that below) or seal the jar so that the cake will last.

In this post, I will teach you the second method. 

Why Make Mason Jar Cakes:

Here are some ideas of why and when to serve them:

• Treats for birthday parties
• Mini desserts
• Personalized cake
• Portable treat (think your next picnic)
• Different kinds of cake for each family member
• Wedding showers
• Valentine’s Day
• Birthday gifts (you can even send them in the mail)
• Christmas presents (also great for sending by mail)

This post contains affiliate links, which means I make a small commission at no extra cost to you. You can read my full disclosure.

What is The Best Glass Jar:

• Weck jars: These Weck jars are my preferred glass jars because they are very sturdy and heavy-duty, have straight sides (cakes come out easily and clean), and come in different sizes. I have an entire blog post about how they compare to Mason jars. 
• Mason jars: Most people are familiar with and have lots of them. Enough said. You can either use a pint-sized jar or a smaller size.
• Repurposed glass jars: There is nothing wrong with using clean jam jars as long as they have a lid with a rubber seal.  

Note: Whether you can repurpose and reuse glass jars is mostly a matter of who you ask. You can read this article for an official guideline. I personally reuse and repurpose glass jars all the time but you should do your own research and determine what you are comfortable with!

Mason Jar Cake Recipe:

Since this post is more about a method than a specific recipe, you can really use any of your favorite cake recipes. It is also a great way to use a boxed cake mix.

However, sponge cakes or simple yellow cakes work the best. If you are just starting out and want your jar cake to last for months, I do not recommend moist cakes such as cheesecake, carrot cake, or cakes with frosting. 

You CAN bake any cake in a glass jar but then you will have to keep it in the refrigerator (more on that below).

Other Ingredients and Tools:

Regardless of what recipe you are using, you will still need:

• Some fat: You can use butter, vegetable oil, or cooking spray to coat the bottom and sides of the jar.
• Some flour: I recommend sprinkling some flour on the bottom of the jar to prevent any sticking. Alternatively, you can use semolina flour, corn meal, rolled oats, or cocoa powder (especially if you’re making a chocolate cake or are using chocolate chips)
• Optional: You can use parchment paper and cut out rounds that fit exactly in the bottom of the jar to make it easier to remove the cake. A biscuit cutter helps cut out the rounds.
• Pastry brush: This helps spread the grease evenly in the jars. 
• Jar lifter: You might like to use a jar lifter for the hot jars. Alternatively, you can use oven mitts or potholders.

Important Tips to Follow:

1. Remove the oven rack or baking sheet before you even turn on the oven. If you put a cold glass jar on a hot rack, it will crack!
2. Be sure to use clean jars and lids. I don’t sterilize mine but they should be free of any soap residue. 
3. Grease the bottom of the jar and the sides of the jar but DO NOT get any fat on the rim. That might prevent a proper seal from happening.
4. You can sprinkle some nuts, extra flour, or semolina on the bottom of the glass jar to make it easier to remove the cake. 

How Long Does Cake in A Jar Last: 

That depends on how you want to store them:

• In the refrigerator: If you can and want to keep them in the refrigerator, these jar cakes will last for weeks. Be sure to add a tight lid and do not add any frosting until you are ready to serve them. They make such an easy dessert.
• At room temperature: If you would like to keep the jar cakes at room temperature, they should last about 4-6 months, depending on how much protein (eggs, milk), starch, and moisture content. You will need to follow one of the methods in the next paragraph! 

However, you can bake a cake in a jar, properly seal it, and keep it in the refrigerator for up to 6 weeks without any problems. 

How To Make The Cake Last:

There are 2 main methods to preserve these mini cakes:

1. Seal them hot: Remove the jar with the cake from the oven. Have the jar lids (or lids and rubber seal if you’re using Weck jars) in a bowl of very hot water. Place the hot lid or lid and rubber seal on the glass jar. Tighten the lid or add the clamps. You will see some water condensation but that is okay!
2. Waterbath: Bake the cakes in the jar and let them cool down a bit. Place the clean lids on the jars. Line a pot with some cloth, and place the jars in the pot (either next to each other or on top of each other). Fill the pot with hot water to about 1/2″ below the top of the highest jar. Gently bring the pot to a boil and simmer at 176˚F (80˚C) for 30 minutes. 
3. Hot oven: You can also bake the cakes, let the cake cool down for 10 minutes, and close them with clean lids. Place them in the hot oven at 212˚F (100˚C) for 30 minutes. 

Common Questions:

How much batter do I need? That depends on how many jars you would like to fill. I often recommend using half of your cake recipe and having at least 4 larger jars or 6 smaller jars. You can also pour any remaining cake batter into a smaller loaf pan and bake that along with the jars.

How long do they need to bake? That will depend on the size of your jar. If you are putting the cakes in a preheated oven at 350˚F, a cake in a smaller jar might take around 25 minutes to bake. Cakes in something like pint mason jars might take around 30 minutes to bake.  I recommend using a cake tester or toothpick to see if the cakes are done. 

How do I know if the mason jar cake is still good? If your jar cakes go bad, they become slightly sour but you will not see any bulging or bad seals. Some people still eat a sour cake. Even though I don’t recommend it, you will not die from it! Apparently, some cakes might even last longer and this German YouTube channel has more information on it.