Our Butter Rum Buttercream Frosting is soft, creamy, and delicious this frosting tastes just like a Butter Rum Hard Candy. Homemade frosting has never been better.

Closeup on three cupcakes topped with The Best Butter Rum Buttercream Frosting sitting on a cutting board next to a bunch of cranberries.

We love how this delicious Butter Rum Buttercream Frosting turned out!  Creamy and buttery with just a hint of rum extract, it tastes just like a butter rum hard candy.  Your family will beg you to make this yummy frosting again and again.

How to Make

Collage image showing the steps for mixing the butter and the Rum Extract to get the best flavored frosting.

Step 1: Add the “slightly softened” butter (somewhere in between straight out of the refrigerator and room temperature) to the mixing bowl along with the Rum Extract.
Step 2: Mix the butter and Rum Extract together until they are fully combined (about 2 minutes on medium speed.) You want the extract to fully meld with the butter to get the best-flavored frosting possible.
Step 3: Scrape the sides of the bowl down before moving on to the next step of the recipe.

Collage image showing the steps for adding the powdered sugar to the frosting.

Step 4: We use a food scale to measure the Powdered Sugar, to measure 1 pound of Powdered Sugar.  If you don’t have a food scale, the equivalent is 4 cups.  Do you need to sift the Powdered Sugar? We don’t normally do that but instead rely on our mixer to break up any lumps during the mixing process.
Step 5: Add the powdered sugar to the mixing bowl.  
Step 6: Start your mixer (or electric beater) on the lowest setting. (Two Sisters Tip: place a clean dishtowel around your mixer to keep the sugar from flying out.)  Keep on low until the butter and sugar are incorporated (about 30 seconds), remove the dishtowel, and scrape down the sides of the bowl. Increase the mixer speed to medium-high and mix for 30-45 more seconds until the frosting starts to be light and fluffy.
Step 7: Now it is time to taste your frosting. You are trying to determine if the consistency is correct or if it needs a tiny bit more Rum Extract. Depending on how it tastes, you will take the next step.  If the frosting has the right taste but is too thick, add some milk and mix again to check to see if it is now the right consistency.  How much milk? That depends on the state of your frosting. A good rule of thumb is to add the milk a teaspoon at a time. You can check out our FAQ section below to see some other advice on making the perfect batch of frosting.

Collage image showing the steps for adding food coloring to the frosting.

Steps 8-9: You can leave the frosting white, but we wanted it to be the color of a Butter Rum Hard Candy.  We added 1 regular-sized drop of yellow food coloring and 1 very small drop of brown to get this pretty golden color. Add the food coloring and then mix until the color is thoroughly combined with the frosting.

How to Serve

Closeup on a decorating bag filled with Butter Rum Frosting sitting in front of a batch of unfrosted chocolate cupcakes.

How much frosting will you need?  That always depends on how thick or thin you apply the frosting or how much decorating you do but here are a couple of guidelines. Our recipe should make enough Butter Rum Frosting to cover a 9″ x 13″ sheet cake or a two-layer 8″ cake.  If you are making cupcakes, you should be able to frost 24 cupcakes if you apply the frosting with a knife.  If you swirl on the frosting with a pastry bag you should be able to frost 15-18 cupcakes depending on the size of the swirl.

Expert Tips and FAQ’s

Does the frosting need to be refrigerated?

No, the frosting does not need to be refrigerated. For example, brownies frosted with this Butter Rum Icing would be fine left out on the counter for 2-3 days if the pan was tightly covered with aluminum foil. That said, we usually refrigerate our frosted desserts to keep the baked good from going stale even if the frosting would be fine. We think frosting tastes best at room temperature so we will then remove the item from the refrigerator a couple of hours before we will serve them.

How do I store any leftover frosting?

Frosting stored in an air-tight container in the refrigerator should be good for up to a week. If you carefully wrap the frosting in order to avoid freezer burn, the frosting should be fine in the freezer for 3-4 months.

What should I do if my frosting turned out too thick?

Add another teaspoon of milk and mix again. Continue to add the milk, a teaspoon at a time, until the frosting is the consistency that you like it

What should I do if my frosting turned out too thin?

Temperature plays a big part in the consistency of frosting. A thin frosting could mean that the butter has gotten overworked and is too melted. The first thing to do is refrigerate the frosting for an hour and then check to see if the frosting has set back up again. If not, the next step is to add more powdered sugar or cornstarch. Start with either 1/2 cup of Powdered Sugar or 1 tablespoon of Cornstarch. Mix again and see if the consistency is better.

Is there a substitute for milk?

Yes. You can use Half n’ Half or Whipping Cream or even almond milk or another milk substitute.

Closeup on a chocolate cupcake topped with The Best Butter Rum Buttercream Frosting sitting on a cutting board.

Other Frosting Recipes You Will Love

The Best Butter Rum Buttercream Frosting

The Best Butter Rum Buttercream Frosting

Yield 2 1/2 cups
Prep Time 10 minutes
Total Time 10 minutes

Our Butter Rum Buttercream Frosting is soft, creamy and delicious this frosting tastes just like a Butter Rum Hard Candy. Homemade frosting has never been better.

Ingredients

  • 1 cup Butter, slightly softened (We use Salted Sweet Cream Butter)
  • 1 teaspoon Rum Extract
  • 1 pound Powdered Sugar (or 4 cups)
  • 1-2 tablespoons Milk (if needed)
  • Food Coloring - Yellow & Brown (optional)

Instructions

  1. Add the “slightly softened” butter (somewhere in between straight out of the refrigerator and room temperature) to the mixing bowl along with the Rum Extract.
  2. Mix the butter and Rum Extract together until they are fully combined (about 2 minutes on medium speed.) You want the extract to fully meld with the butter to get the best-flavored frosting possible.
  3. Scrape the sides of the bowl down before moving on to the next step of the recipe.
  4.  We use a food scale to measure the Powdered Sugar, to measure 1 pound of Powdered Sugar.  If you don’t have a food scale, the equivalent is 4 cups.
  5. Add the powdered sugar to the mixing bowl.  
  6. Start your mixer (or electric beater) on the lowest setting. Keep on low until the butter and sugar are incorporated (about 30 seconds), remove the dishtowel, and scrape down the sides of the bowl. Increase the mixer speed to medium-high and mix for 30-45 more seconds until the frosting starts to be light and fluffy.
  7. Taste your frosting. You are trying to determine if the consistency is correct or if it needs a tiny bit more Rum Extract. Depending on how it tastes, you will take the next step.  If the frosting has the right taste but is too thick, add some milk and mix again to check to see if it is now the right consistency.  How much milk? That depends on the state of your frosting. A good rule of thumb is to add the milk a teaspoon at a time. 
  8. You can leave the frosting white, but we wanted it to be the color of a Butter Rum Hard Candy.  We added 1 regular-sized drop of yellow food coloring and 1 very small drop of brown to get this pretty golden color. Add the food coloring and then mix until the color is thoroughly combined with the frosting.

Did you Make this Recipe? Leave a review below, then snap a picture and tag @twosisterscrafting on Instagram so we can see it!

If you are looking for more tips and tricks for making that perfect batch of homemade frosting we have a few other posts you might want to check out: