High Altitude Table Runner Birthday Cake
This table runner cake has a long, rectangular shape that's ideal for serving to birthday party guests. The cake is a soft and fluffy vanilla cake with sprinkles, vanilla buttercream, and a hint of almond extract.
All recipes on Curly Girl Kitchen are developed for high altitude at 5,280 feet. See FAQs for adjusting to higher or lower elevations.
Equipment
- Stand Mixer with Paddle Attachment
- 13x18 Rimmed Baking Sheet (+ parchment paper)
Ingredients
Cake
- 1 ½ cups (12 oz) unsalted butter, softened to room temperature
- 1 ¾ cups granulated sugar
- 6 egg whites room temperature (you can use fresh egg whites, or 3/4 cup liquid egg whites from a carton)
- 3 cups cake flour, fluffed, spooned and leveled
- 3 ½ tsp baking powder
- ½ tsp coarse Kosher salt (if using table salt, use half the amount)
- 1 ½ cups whole buttermilk, room temperature
- ½ cup sour cream
- 2 tsp vanilla extract
- 2 tsp almond extract
- ½ cup rainbow sprinkles, preferably quins or confetti sprinkles
Buttercream
- 3 ½ cups unsalted butter, softened to room temperature
- 7 cups powdered sugar
- 1 tbsp meringue powder (optional)
- ½ tsp coarse Kosher salt (if using table salt, use half the amount)
- 4 tsp vanilla extract
- 2-4 tbsp milk or cream, only if needed
Instructions
Cake
- Preheat the oven to 350 F, and position a rack in the center of the oven. Line a 13x18 inch rimmed baking sheet with parchment paper. It's helpful to snip the paper at the four corners of the pan, so that it fits snugly into the pan, with the paper rising up above the pan's sides on all sides. The paper must be higher than the pan's edges, so that the cake can rise up the paper as it bakes and not spill over the edge. Lightly spray the paper with non-stick baking spray.
- In the bowl of your stand mixer fitted with the paddle attachment, beat the butter and sugar on medium speed for 10 minutes, scraping the bowl occasionally, until very light and fluffy. Beat in the egg whites, one at a time, beating each for about 15 seconds before adding the next egg white. Scrape the bowl down and beat for 15 more seconds.
- In a separate bowl, sift together the cake flour, baking powder and salt. In another bowl, whisk together the buttermilk, sour cream, vanilla and almond extracts.
- With the mixer on low, add the flour mixture in three additions, alternating with the buttermilk mixture, starting and ending with the flour, being careful not to over-mix. Add the sprinkles and use a large spatula to briefly fold the sprinkles in, as well as any remaining bits of flour.
- Pour the batter into the pan, and use a large offset icing spatula to smooth out the top of the batter as evenly as possible.
- Bake the cake on the center rack for about 28-30 minutes, until a toothpick in the center comes out clean or with moist crumbs clinging to it, and the center springs back when lightly touched.
- Set the pan on a wire rack, and let cool at room temperature for 30 minutes, then set the pan in the refrigerator to cool completely before assembling. It's helpful if the cake is slightly firm and cold from the fridge for assembling the layers.
Buttercream
- In the bowl of your stand mixer fitted with the whisk attachment, beat the butter for one minute until smooth.
- Whisk together the powdered sugar, meringue powder and salt. With the mixer on low, add the powdered sugar mixture by spoonfuls, mixing until combined.
- Add the vanilla and almond extracts, then whip on medium speed for 4-5 minutes until very light and fluffy, scraping the bowl occasionally. Add the milk only if needed for desired consistency. Turn the speed down to "stir" and mix for 1 more minute.
- This makes a large batch of buttercream, enough for frosting the cake, with some leftover for the decorative piping shown in the video.
Assembly
- Slide the cooled cake off the baking sheet onto your counter. Measure the width of the cake, and cut the cake into thirds, lengthwise, so that you have three 18-inch long sections of cake. I used a rolling pizza cutter to cut the cake. Now use a sharp knife to go back through the cuts again, this time scoring the paper. Separate the sections of cake, so that each section is sitting on its own strip of paper.
- Carefully, lift one of the sections of cake and invert it onto your serving board, then peel off the paper. Frost the cake with a layer of buttercream.
- Repeat with the 2nd and 3rd layers of cake. If needed, you can use a knife to trim any uneven edges.
- Frost the cake all over with a thin crumb coat of buttercream, and chill for 15 minutes.
- Frost the cake all over with a final coat of buttercream, using a bench scraper to smooth the sides and top, or an icing spatula to create swirls all over.
- Before the buttercream crusts over, scatter the cake with sprinkles.
- To decorate the cake, you can tint the remaining buttercream with gel food coloring and add decorative piping. For the pink border around the top and bottom edges of the cake, I used tip 18. For the green drop flowers, I used tip 1M.
Video
Notes
- Store leftover cake in an airtight container or cake carrier, at room temperature, for up to 3 days.
- Leftover buttercream can be frozen in freezer bags for up to 3-6 months, and used for other projects.
- If you don't have buttermilk, you can make sour milk with whole milk and lemon juice. Simply replace one tbsp of the milk with lemon juice.
- I used a beautiful 20-inch long marble board to display my cake. I'd recommend checking your local Home Goods stores for these types of boards - you can usually find various sizes of wood and marble boards for very affordable prices.
- To make an even longer table runner cake for 40 people, you can double this recipe and assemble two 18-inch cakes end to end.
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