How to Thicken Frosting: Choose From These 5 Easy Ways

​I love baking cupcakes and I take a special interest in topping them with different frosting designs and flavors. If you’re a baker like me, there’s a big chance that you’ve encountered a batch of runny frosting before. Thin frosting is very hard to add on cupcakes because they tend to fall off or not spread evenly.

Getting the right frosting consistency is important if you want to come up with the perfect batch of cupcakes to serve at parties or as simple desserts after meals. Today, I will share different ways on how to thicken frosting, depending on the type you’re serving and the available ingredients you have in your kitchen.

Things You Need


Thickening agent

There are many thickening agents you can choose from, depending on the type of frosting you need to fix. The most common one is powdered sugar, although some bakers prefer cornstarch because it doesn’t add any flavor to the frosting.

You can also use meringue powder or heavy cream to make your frosting thicker. Butter is often used to thicken cream cheese frosting and Italian buttercream.

While flour is technically another thickening agent, you should only use it for cooked frosting. Raw flour tastes weird, so don’t use it to thicken cold frosting.


  • Bowl
  • Electric or hand whisk or mixer


Option 1: By adding powdered sugar

Powdered sugar is the most common thickening ingredient for frosting. This is because most frosting is composed largely of sugar to begin with.

It is important to add just the right amount of sugar because most frostings are already sweet. Adding too much sugar might make your frosting too thick or too sweet. When this happens, you will need to add more liquid into the frosting, which defeats the purpose of adding the thickening agent in the first place.

I recommend adding ½ cup of powdered sugar per batch. Mix the frosting well using a hand whisk or electric mixer until the frosting sticks to the whisk instead of falling off.

Optional: Add meringue powder

An optional step is to add meringue powder to balance out the sweetness of the powdered sugar. Meringue powder does not have its own taste so you can safely add it to make your frosting thicker.

As a baseline, add 1 to 2 teaspoons of meringue powder for every ½ cup of powdered sugar. If you’re using less than half a cup of sugar, then you can just leave out the meringue powder altogether.

Option 2: By adding cornstarch

​Some bakers prefer using cornstarch because it doesn’t add any taste to the frosting. I personally like using this for frosting that are already on the super sweet side.

Before mixing in the cornstarch with your thin frosting, you may want to grind it in an electric grinder first. This helps to further break it down into a soft powder and makes it easier to mix it in your base ingredient. This also prevents it from forming small clumps all over your frosting.

Add ½ teaspoon of cornstarch into a bowl of frosting and whisk it by hand or by an electric mixer. Add another ½ teaspoon if you still find the frosting’s consistency a bit thin for your taste.

Option 3: By adding heavy whipping cream

If you need a fluffy frosting for your cupcakes or as icing on a cake, then you may want to use heavy whipping cream as a thickening agent.

To do this, add 3 to 4 tablespoons of the cream into your bowl of frosting and whisk with an electric mixer. Check the consistency and add more, preferably at 1 tablespoon increments, until the frosting becomes light and frothy.

Option 4: By adding butter

​Butter is another great thickening agent, especially if your frosting already has butter as an ingredient.

Add 1 tablespoon of butter at a time and mix well with a hand whisk or electric mixer. To make it easier to mix in, allow butter to soften slightly before adding it to the frosting. Don’t let it melt though!

Don’t worry if the consistency of your frosting doesn’t immediately improve. Butter usually liquefies when exposed to heat, so you may want to refrigerate your frosting for a few minutes to allow the butter to properly set in.

Option 5: By adding flour

​If you’re cooking frosting and it turns out to be a bit runny, you can add flour into the pot to make it thicker. Remember, however, that flour only works as a thickening agent when you’re making warm frosting because it tastes weird when it is not cooked properly.

Add 1 to 2 teaspoons of flour into the warm frosting and stir slowly over low heat for a few minutes. Once you notice that the frosting is starting to thicken, remove the pot from the stove and let it cool to room temperature.


Nobody likes runny frosting on their cupcakes, and these options will help you make sure this never happens. But don’t limit yourself to the options I listed above. There are other thickening ingredients you can use - you just need to check what’s available in your kitchen!

Is this article helpful? Do you have a favorite way of making frosting thicker? Please share them in the comments’ section below. I’d like to hear more about it! And don’t forget to share this article and my tips with your baker friends.

Say goodbye to runny frosting and hello to thick, fluffy ones!

Jack Smith

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