High-Altitude Coconut Cake

This is one of the first cakes I ever really took apart and rebuilt for high altitude. I was still a pretty new baker back then, and I kept having cakes fall — that sunken-middle disappointment where everything looks right going into the oven and wrong coming out — and for a long time I couldn’t figure out why.

I have a chemistry degree, and not understanding why something isn’t working bothers me more than the failed cake itself. So I started digging into what thin mountain air actually does to a cake: how it changes the way flour holds structure, how liquids evaporate faster than they should, how sugar and eggs behave differently without as much atmospheric pressure pushing back on them, and why baking powder that behaves perfectly at sea level can blow a cake apart at 5,280 feet. This coconut cake is where a lot of that research first came together into a recipe that actually worked — not just once, but every time.

If you’re baking closer to sea level, use the original Old Fashioned Coconut Cake recipe instead — same cake, same story, just without the altitude adjustments below.

Why This Cake Needs Adjusting at Altitude

As a rule of thumb, once you’re above about 3,000 feet, baking powder is the first thing worth watching closely. By 5,000 feet — where I am, at 5,280 feet in Denver — the adjustments aren’t optional anymore. A handful of things are working against you all at once:

• Baking powder does too much, too fast. Lower air pressure means the gas bubbles it creates expand more than they would at sea level. Use the same amount called for in a sea-level recipe and the cake over-expands before the structure can set — which is exactly what causes that sunken middle. This recipe cuts the baking powder by half.
• Flour needs to do more of the work. With less atmospheric pressure to help hold a cake up, the batter needs a slightly stronger structural scaffold to lean on instead. A little extra flour helps compensate.
• Liquid evaporates faster. Thinner air pulls moisture out of the batter more aggressively while it bakes, so a touch more milk keeps the crumb from drying out.
• Sugar gets scaled back slightly. Sugar weakens a cake’s structure (it’s part of why it’s so tender at sea level) — at altitude, where structure is already working harder, pulling back a little helps the cake hold itself together.
• Oven runs hotter, for less time. A higher temperature sets the structure faster, before the leavening gases have as much time and opportunity to over-expand.

None of these adjustments are guesswork — they’re the result of testing this specific cake, repeatedly, until it stopped falling.

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5 from 1 vote

High-Altitude Coconut Cake

This is the high-altitude version of my Old Fashioned Coconut Cake recipe.  It adjusts the flour (increase), sugar (decrease), liquid (increase), baking powder (BIG decrease!), bake temperature (increase) and bake time (decrease).  It is adjusted to 5,280 feet, but if you are significantly higher, you'll need to change the proportions just a little more to achieve perfect results.  See my article on high-altitude adjustments here.

Prep Time20 minutes mins

Cook Time40 minutes mins

Total Time1 hour hr

Course: Dessert

Cuisine: American

Keyword: High-Altitude Coconut Cake

Servings: 12 Servings

Calories: 388kcal

Author: Don Herman

Ingredients

• 387 grams Flour 1/2 all-purpose, 1/2 cake flour
• 405 grams Granulated Sugar
• 1 1/4 tsp Baking Powder
• 1/2 tsp Salt
• 5 lg Egg Whites
• 10 tbsp Milk 133 ml
• 1 tbsp Natural Coconut Extract See below if your store doesn’t carry this.
• 1/2 cup Unsalted Butter 57 grams, softened, but not melted
• 3/4 cup Unsweetened Coconut Milk 177 ml. It should be about 15% fat content. It replaces some of the butter, so don’t use the type in a box you pour on cereal.

Coconut Cream Cheese Frosting and Whipped Filling

• 8 oz Cream Cheese room temperature
• 1/2 cup Butter room temperature
• 4 cups Powdered Sugar
• 1 tsp Natural Coconut Extract
• 10 oz Shredded Coconut sweetened or unsweetened

Filling Between Layers

• 1 cup Frosting from above
• 1 cup Heavy Whipping Cream

Instructions

• Preheat oven to 370 F (190 C).
• Grease and flour two 8 or 9-inch cake pans. (Lining with parchment can make removing the cakes easier, but I never have a problem in this dry climate. See how to create a cake pan liner below.)
• In a medium bowl, whisk the egg whites, milk and coconut extract just until frothy.
• In a mixer bowl, add the flours, sugar, baking powder and salt. Mix with a whisk. Add the butter and coconut milk and mix on low with a paddle attachment just until moistened.
• Add the egg white mixture in a few additions, mixing just until incorporated, then beat for two minutes.
• Pour the batter into the prepared pans. I use a small postal scale to weigh them out so that I divide it evenly. Bake for 31 to 34 minutes, then test with a toothpick to see if it comes out clean. Add two minutes more if it comes out wet.
• Remove from the oven and let cool for about 10 minutes, then remove from pans and cool completely on a rack.
• While the cakes are cooling, use the warm oven to toast your coconut. Simply sprinkle the coconut on a cookie sheet in a thin layer and set it in the oven at 350 F for about two minutes. Stir the flakes and watch them for another two minutes or so. When they’ve toasted to golden, remove and cool.

Coconut Cream Cheese Frosting and Whipped Filling

• Cream together the cream cheese and butter. Add the coconut flavor. Then add the powdered sugar, one cup at a time. I cover my mixer with a very light tea towel to avoid sugar powder spreading all over the kitchen! Once it’s smooth, add a tablespoon of the coconut milk or regular milk to achieve a spreadable consistency (I didn’t have to add any).
• If the icing is too thick for spreading, add a teaspoon or two of coconut milk and blend to the desired consistency.
• For the filling, simply whip 1 cup of heavy whipping cream until medium peaks form, then gently blend in 1 cup of the cream cheese icing.

Assembly

• I divided my cake layers into four pieces, using a cake leveler. I used the whipped cream between each layer, then iced the outside of the cake with the cream cheese frosting. Lastly, I sprinkled the toasted coconut, using my palm to “bounce” the flakes onto the sides of the cake.

Notes

Using Coconut Milk: There are many varieties on the market. Goya is a good brand, but whatever you use, make sure it’s about 15% fat. You’ll need to open the can and give it all a good stir before you measure it, as much of the fat will have solidified in the can over time. You want to stir it smooth before measuring.

If you made this, I’d love to hear how it turned out — leave a star rating and drop a comment below. It helps me out, and it helps other high-altitude bakers know what to expect.

A Few Things That Make This Cake Work

A handful of technique notes that matter regardless of altitude, but that I learned the hard way while working this recipe out:

• Use real canned coconut milk, not the refrigerated “coconut milk” from the cereal aisle — you want something close to 15% fat. It separates in the can, so stir it thoroughly before measuring.
• Don’t skimp on the coconut extract. A good-quality one makes a bigger difference in the final flavor than you’d expect from such a small amount.
• Keep the filling as whipped cream, not more cream cheese frosting. Cream cheese frosting on the outside and whipped cream between the layers keeps the whole cake from turning into a dense, overly rich block.
• Toast your own coconut for the coating, and watch it closely. Not every brand of shredded coconut toasts evenly — plain sweetened flakes (Baker’s brand, specifically) have worked better for me than the unsweetened “natural”/organic varieties, which tend to toast unevenly or scorch at the edges.