Buttered rum cupcakes are brushed with butter rum syrup and topped with rum buttercream. This is a delicious fall dessert!

buttered rum cupcakes topped with rum frosting and cinnamon on unwrapped paper cupcake liner

Being born in January does not guarantee that you are a winter person. I make the best of the chilly weather by baking in the kitchen of course. It’s the big 2-5 this year and to celebrate I baked buttered rum cupcakes. They are a boozy comfort food treat.

Why this recipe works: The spiced rum flavor is evident in these cupcakes. There is rum in the cupcake batter, brushed on top of the cupcakes and in the buttercream frosting. There is not question that this is a boozy dessert!

buttered rum cupcakes topped with frosting, cinnamon and rum on wire cooling rack
buttered rum cupcakes ingredients in bowls and labeled

Cupcakes step by step instructions

  1. Preheat oven to 350 F. Line a muffin tin with paper liners and set aside.
  2. Brown the butter on the stove top. Let it cool completely.
  3. Whisk dry ingredients—flour, baking soda, baking powder, cinnamon, nutmeg and salt.
  4. Combine wet ingredients—browned butter, buttermilk, butter, egg, brown sugar, sugar and vanilla.
  5. Alternate adding dry ingredients and rum to the wet ingredients. Mix just until combined and transfer batter to prepared muffin tin.
  6. Bake cupcakes for 18 minutes. Cool cupcakes in the tin for 5 minutes before transferring to a wire rack to cool completely.
photo collage demonstrating how to make batter for buttered rum cupcakes
mixing bow and muffin tin filled with rum cupcake batter

How to make buttered rum syrup

The best part about these cupcakes is the buttered rum syrup. It adds that unmistakable buttered rum flavor to each cupcake and keeps the cupcake boozy! To make buttered rum syrup, melt butter in a saucepan over medium heat until melted. Add the rum and heat until warm. Add cornstarch and mix until the syrup is thick. Cool completely before brushing the cupcakes.

How to make rum buttercream frosting

This recipe uses a variation of my buttercream frosting, but I added cinnamon and rum to the frosting for flavor. Beat the butter, vanilla, rum and cinnamon until smooth and creamy. Add confectioners’ sugar with the mixer running on low, then increase speed to high until light and fluffy.

If you have leftover rum, try making these easy rum balls.​​​​​​​

photo collage demonstrating how to make buttered rum syrup
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Buttered Rum Syrup (above)

photo collage showing ingredients and steps to make rum buttercream frosting
Rum Buttercream Frosting (above)

Helpful recipe tips

The best tip I can give you for any baking recipe is to use a kitchen scale, especially for cakes. Scales provide weight, which is more accurate than using measuring cups. Keep the oven door closed until cupcakes are done. Every time you open the oven door, air escapes and the cupcakes will lose their rise.

Let cupcakes cool completely before adding buttered rum syrup and rum buttercream frosting. If the cupcakes or buttered rum syrup are warm, the frosting will melt.

Frequently Asked Questions

What is the best rum to use?

Any type of spiced rum will work in this recipe (just make sure it’s spiced!) Of course, the higher quality rum you have the more flavor there will be in the cupcakes. I personally like Kraken spiced rum, but Captain Morgan works well too.

What should I do if the frosting is thin/is melting?

The butter should be room temperature, but if you are making these in the summer or in a warm/humid climate then the butter might be too warm. Place the frosting in the refrigerator for 10 to 15 minutes and try frosting again. Keep cupcakes in the refrigerator in warm climates.

How to store buttered rum cupcakes:

Cupcakes will keep in an airtight container at room temperature for 3 days or in the refrigerator for 5 days.

Can you freeze cupcakes?

Yes. Once the cupcakes are cooled, individually wrap them and place in an airtight container in the freezer. Freeze for up to 1 month for best flavor. Defrost in the refrigerator before bringing to room temperature and adding the syrup and frosting.

buttered rum cupcake with squeeze shot tube filled with rum inserted in cupcake

This may be one of the best birthday treats I have ever made myself (German chocolate cake is a close second). Cocktail cupcakes are always a science experiment in the kitchen for me and each time they turn out to be better than the last. If you enjoyed this recipe, try my Dark n’ Stormy cupcakes made with rum and ginger beer!

But in all seriousness these buttered rum cupcakes are divine and will warm up those winter blues. If you try this recipe, tag @ifyougiveablondeakitchen on social media and I’ll share my favorites on Instagram!

tops of buttered rum cupcakes with frosting and mini injector of rum inserted to cupcakes

Buttered Rum Cupcakes

Buttered rum cupcakes are brushed with butter rum syrup and topped with rum buttercream. This is a delicious fall dessert! 
5 (7 ratings)

Ingredients

Spiced Cupcakes

  • cup (75 g) unsalted butter, room temperature
  • 1 large egg, room temperature
  • 1 cup (236 ml) buttermilk, room temperature
  • 1 cup (200 g) dark brown sugar
  • cup (66 g) sugar
  • 1 ½ teaspoons pure vanilla extract
  • 2 ½ cups (312 g) all purpose flour
  • 1 ½ teaspoons cinnamon
  • ½ teaspoon nutmeg
  • 1 teaspoon salt
  • 2 teaspoons baking powder
  • 1 teaspoon baking soda
  • ½ cup (118 ml) spiced rum
  • ½ cup (118 ml) water

Rum Buttercream Frosting

  • 1 cup (226 g) unsalted butter, room temperature
  • 3 cups (360 g) confectioners' sugar
  • ½ teaspoon cinnamon
  • ½ teaspoon vanilla extract
  • 3 to 4 tablespoons (45 ml) spiced rum

Buttered Rum Syrup

  • 2 tablespoons (28 g) unsalted butter
  • 2 tablespoons (30 ml) rum
  • 1 tablespoons cornstarch

Instructions 

Rum Cupcakes

  • Preheat oven to 350° F. Prepare cupcake tin with cupcake liners.
  • In a medium bowl, whisk together the flour, cinnamon, nutmeg, salt, baking powder and baking soda. Set aside.
  • In a small saucepan, heat the butter over medium-low heat, whisking constantly. The butter will start smelling sweet and brown specks will appear, remove from heat and continue whisking for 30 more seconds. Pour into stand mixer and let cool. Once the butter is cool, add the buttermilk, egg, sugars and vanilla, and mix until well combined.
  • In a cup, combine rum and water. Now with the mixer on low and working in batches, alternate adding the flour mixture and the rum mixture into the batter, beginning and ending with the flour. Once both mixtures are added to the batter, continue mixing for another 10 seconds to ensure all the ingredients are combined. Scrape down the sides if necessary.
  • Fill each cupcake liner about three-quarters full. Bake for 15-18 minutes, until a toothpick inserted in the center of a cupcake comes out clean. Let the cupcakes cool in the tin for 5 minutes and then transfer to a wire rack to cool completely.

Rum Buttercream Frosting

  • In the bowl of a stand mixer, use a whisk attachment on medium speed to cream the butter until light and fluffy, about 90 seconds. Gradually add the powdered sugar, cinnamon, and vanilla extract. Beat on medium speed until creamy.
  • Add the rum, starting with one tablespoon and add more until you reach desired consistency (I ended up using 4 tablespoons). Beat on high for 2-3 minutes, until fluffy and whipped.

Butter Rum Syrup

  • In a sauce pan, melt butter over medium heat. Gently add the rum and heat until warm, about 30 seconds. Add the corn starch and whisk until you reach a thick syrup consistency. Remove from heat and transfer to a bowl to cool.

Assembly

  • Brush the top of the cupcakes with buttered rum syrup. Transfer the frosting to a frosting bag with desired tip and frost the cupcakes in a swirl motion. Dust with cinnamon if desired. Store in an airtight container at room temperature.

Notes

Decoration: For an added touch, insert cupcakes with a rum-filled alcohol squeeze tube. You will need about 1/2 cup additional rum for this.
Store cupcakes in an airtight container at room temperature for 3 days or in the refrigerator for 5 days.
Freeze cooled cupcakes wrapped individually and in an airtight container for up to 1 month. Defrost in the refrigerator before bringing to room temperature and adding syrup and frosting.
Recommended tools:
Serving: 1cupcake, Calories: 375kcal, Carbohydrates: 50g, Protein: 3g, Fat: 16g, Saturated Fat: 10g, Cholesterol: 50mg, Sodium: 215mg, Potassium: 104mg, Fiber: 1g, Sugar: 36g, Vitamin A: 494IU, Calcium: 55mg, Iron: 1mg

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