How to Make Smooth Buttercream Cakes

A Beginner’s Step-by-Step Guide

A beautifully smooth buttercream cake can make even a simple cake look professional and elegant. But if you’re a beginner, getting that perfectly smooth finish can feel frustrating. You may end up with air bubbles, uneven sides, visible cake crumbs, or rough edges.

The good news is that smooth buttercream cakes are not only for professional cake decorators. With the right buttercream consistency, tools, and technique, you can achieve a clean and smooth finish at home.

In this guide, I’ll show you how to make a smooth buttercream cake step by step.

But before then, what is buttercream?

What Is Buttercream?

Buttercream is a creamy frosting made primarily from butter and icing sugar. Depending on the recipe, other ingredients such as milk, whipping cream, vanilla, or other flavorings may be added.

It is commonly used to fill, cover, and decorate cakes because it is easy to work with and can be flavored and colored in many different ways.

Ingredients You Need

For a basic buttercream frosting, you will need:

• unsalted or salted butter – 200g
• icing sugar – 500g
•  milk – 1 tablespoons
• 1 teaspoon of flavor. (it could be vanilla extract, banana, coconut flavor)
• water – 2 tablespoon or more (depends on your brand of margarine)

You can adjust the quantities depending on the size of your cake.

Tools You Need

You don’t need a huge collection of equipment to achieve a smooth buttercream finish. Start with:

• Cake turntable
• Cake scraper
• Spatula
• Cake board
• Hand towel
• Mixing bowl
• Electric mixer / Hand whisk
• Piping bag
• Nozzle
• Spatula
• Serrated knife or cake leveler

A cake turntable and scraper are particularly helpful because they make it much easier to achieve smooth, even sides.

Step 1: Prepare Your Cake

Before you begin decorating, make sure your cake layers are completely cool.

Never frost a warm cake. The heat can soften the buttercream and cause it to slide or melt.

If necessary, chill your cake layers for a short time before decorating. Cold cake layers are generally easier to handle and crumb coat.

Step 2: Make Your Buttercream

Place your softened butter in a mixing bowl and beat/whisk it until it becomes light and creamy.

Gradually add the sifted icing sugar while mixing at a low speed to prevent the sugar from flying everywhere.

Add your flavor and a little milk or cream. Continue mixing until the buttercream becomes smooth and creamy.

Avoid adding too much liquid at once. You want a buttercream that is soft enough to spread but firm enough to hold its shape.

Tip: Don’t Skip the Sifting

Sifting your icing sugar can help reduce lumps in your buttercream, giving you a smoother frosting.

Step 3: Remove Excess Air From the Buttercream

One common reason buttercream cakes have tiny holes and air bubbles is because the frosting contains too much air.

After whipping your buttercream, mix it on low speed for a few minutes.

You can also use your spatula to press and stir the buttercream against the side of the bowl. This helps push out some of the trapped air.

This simple step can make a noticeable difference when you’re trying to achieve a smooth finish.

Step 4: Level Your Cake Layers

Place your first cake layer on a cake board.

If the cake has a dome, use a serrated knife or cake leveler to carefully remove the excess and create a flat surface.

A level cake is much easier to decorate than one with uneven layers.

Step 5: Add Your Filling

Place a layer of buttercream on top of the first cake layer.

Spread it evenly using your offset spatula.

Place the next cake layer on top and gently press it down so the layers are properly aligned.

Continue until all your cake layers are stacked.

Step 6: Apply a Crumb Coat

A crumb coat is a thin layer of buttercream applied around the entire cake to trap loose crumbs.

Don’t worry about making it perfect at this stage.

Use your scraper to spread the buttercream around the cake, then place the cake in the refrigerator for about 15–30 minutes or until the buttercream is firm.

This step is especially important if you’re working with a cake that produces a lot of crumbs.

Step 7: Apply the Final Layer of Buttercream

Once your crumb coat has chilled and set, apply a generous layer of buttercream around the cake.

Add enough frosting to cover the cake completely. It is better to have slightly more buttercream than too little because you need enough frosting for your scraper to work with.

Place the cake on your turntable.

Hold your cake scraper against the side of the cake while slowly turning the turntable.

Keep the scraper steady and allow the rotation of the cake to do most of the work.

Step 8: Smooth the Sides

This is where the magic happens!

Hold your scraper vertically against the side of the cake and slowly rotate the turntable.

Try not to move the scraper back and forth too much.

After each rotation, remove the excess buttercream from your scraper and repeat the process.

If you notice gaps or holes, add a little more buttercream to those areas and scrape again.

Don’t rush this stage. Smooth cakes usually require several rounds of scraping.

If after everything you still don’t get a smooth buttercream, deep your scrapper into a boiling water, shake out the excess water, place gently on the sides of the cake and gently turn the turntable.

Step 9: Smooth the Top Edge

After smoothing the sides, you’ll usually have a small lip of buttercream around the top edge of the cake.

Using your offset spatula, gently pull the excess buttercream from the outside edge toward the center of the cake.

Continue around the cake until you achieve a clean top edge.

Common Mistakes That Prevent Smooth Buttercream Cakes

1. Using Buttercream That Is Too Soft

If your buttercream is too soft, it will be difficult to create sharp, smooth sides.

Add more icing sugar if necessary, or chill the buttercream briefly before decorating.

2. Using Buttercream That Is Too Hard

Very stiff buttercream can make smoothing difficult and may cause you to drag crumbs around the cake.

Allow it to soften slightly or add a very small amount of milk or cream.

3. Skipping the Crumb Coat

Without a crumb coat, cake crumbs can easily become mixed into your final layer of buttercream.

4. Using Too Little Buttercream

Trying to scrape a very thin layer of buttercream can expose the cake underneath.

Apply enough frosting so that your scraper has something to work with.

5. Pressing the Scraper Too Hard

You don’t need to force the scraper against the cake.

Use gentle, consistent pressure while turning the cake.

6. Not Using a Turntable

You can decorate without one, but a turntable makes the process significantly easier and helps you achieve a more even finish.

How to Get Extra-Smooth Buttercream

Here are a few additional tips:

• Use room-temperature butter when making your buttercream.
• Sift your icing sugar.
• Don’t over-whip your buttercream.
• Remove excess air before decorating.
• Make sure your cake layers are level.
• Chill your crumb-coated cake before applying the final layer.
• Use a straight cake scraper.
• Rotate the turntable slowly and consistently.
• Take your time instead of trying to finish the cake quickly.

Can You Get a Smooth Cake Without a Cake Scraper?

Yes!

Although a cake scraper makes the process much easier, you can use a large offset spatula or a straight-edged palette knife.

However, if you plan to decorate cakes regularly, investing in a good cake scraper and turntable is worthwhile.

Final Thoughts

Learning how to make smooth buttercream cakes takes practice. Your first cake may not have perfectly sharp edges, and that’s completely okay.

The more cakes you decorate, the better you’ll become at controlling your buttercream, holding your scraper, and creating an even finish.

Remember: smooth cakes are made with the right buttercream consistency, the right tools, and plenty of patience.

So keep practicing, keep learning, and most importantly, enjoy the process.

Happy baking!