Vibrant Ube Coconut Cake

This Ube Coconut Cake combines the distinctive purple yam flavor of ube with the tropical essence of coconut, creating a stunning purple-hued dessert that's as beautiful as it is delicious. The cake layers are incredibly moist thanks to the buttermilk and oil, while the unique coconut frosting creates a texture that transforms as it sits overnight. The result is a show-stopping cake that balances sweet, nutty, and slightly tangy flavors in every bite.

I first made this cake for my sister's birthday last summer, and my family couldn't stop talking about it. The texture was unlike any cake we'd had before—moist, rich, and with a frosting that transformed into something magical overnight.

Ingredients and Selection Tips:

• All-purpose flour (3 cups/375g): Provides structure without being too heavy. Look for unbleached for best flavor.
• Baking powder (1 tablespoon) & baking soda (¾ teaspoon): These leavening agents work together with the buttermilk to create the perfect rise.
• Kosher salt (1½ teaspoons for cake, ¼ teaspoon for frosting): Enhances flavors and balances sweetness. Don't substitute table salt, which is more concentrated.
• Ube halaya (¾ cup/186g): This purple yam jam is the star ingredient. Find it at Asian markets or online; choose brands with deep purple color and smooth texture.
• Ube paste (1 tablespoon): Intensifies the ube flavor and color. McCormick brand works well.
• Granulated sugar (2¼ cups/450g for cake, 4 cups/800g for frosting): Sweetens and helps create moisture. Use regular white granulated for best results.
• Eggs (6 large): Provide structure and richness. Room temperature eggs incorporate better.
• Buttermilk (1½ cups/360g): Adds tenderness and subtle tang. If unavailable, mix 1½ cups milk with 1½ tablespoons lemon juice.
• Neutral oil (1½ cups/315g): Creates exceptional moisture. Canola or vegetable oil work perfectly.
• Sour cream (two 16oz/454g containers): The base of our unique frosting. Full-fat yields best results.
• Unsweetened shredded coconut (14 cups/700g): Creates texture and coconut flavor. Look for finely shredded rather than flaked for best texture.

Step-by-Step Instructions:

Step 1:

Preheat your oven to 350°F (180°C). Take two 9-inch round cake pans and thoroughly coat the insides with cooking spray, ensuring you reach all corners. Cut parchment paper into circles to fit the bottoms exactly. Place the parchment circles in the pans and spray them lightly as well. This double insurance prevents any sticking issues later.

Step 2:

In a medium bowl, whisk together the flour, baking powder, salt, and baking soda until they're evenly distributed. Whisking rather than sifting at this stage helps incorporate air while ensuring even distribution of leavening agents. Set this mixture aside while you prepare the wet ingredients.

Step 3:

Attach the whisk attachment to your stand mixer. Add the room temperature ube halaya to the bowl and beat on medium speed until completely smooth with no lumps, about 1-2 minutes. The consistency should be like thick jam. Then add the sugar and beat on medium-high speed until combined. Note that you're not looking to cream them together as you would with butter—the mixture should look moist, crumbly, and distinctly purple.

Step 4:

Add the eggs and ube paste to the mixer bowl. Beat on medium speed until fully combined, about 30 seconds. The mixture will become smoother and more uniform in color. Then pour in the buttermilk and oil and beat again until completely incorporated, another 30 seconds. The batter will look quite liquid at this stage—that's exactly what you want.

Step 5:

Switch from the mixer to hand mixing for this step to prevent overmixing. Sift half of the flour mixture directly into the wet ingredients and gently whisk by hand until just combined—a few small lumps are fine. Repeat with the remaining flour mixture, whisking until barely combined. Overmixing will develop gluten and result in a tough cake, so use a light hand.

Step 6:

Divide the batter evenly between your prepared pans—I recommend using a scale for precision, aiming for about 765g per pan. Smooth the tops with an offset spatula. Bake in your preheated oven for 35-40 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs. The cakes should spring back when lightly touched in the center.

Step 7:

Place the pans on a wire cooling rack and allow them to cool for exactly 10 minutes in the pans. This timing helps the cakes set enough to handle while still being warm enough to release easily. Run a small offset spatula around the edges to loosen, then carefully invert onto the wire rack. Peel off the parchment paper, then invert again so the cakes are right-side up. Allow them to cool completely, about 1-2 hours.

Step 8:

Switch to the paddle attachment on your stand mixer. Add the sour cream, sugar, and salt to the bowl and beat on low speed until evenly combined. The mixture will look grainy initially. Add one-third of the coconut and beat on low until incorporated. Add the second third, mix until combined, then add the final third and mix until evenly distributed. The frosting will be thick but spreadable.

Step 9:

Place one cake layer top-side up on your serving plate. Spread exactly 2 cups (450g) of the coconut frosting evenly across the surface, extending it just slightly beyond the edges. Place the second cake layer on top, but position it bottom-side up so you have a completely flat top surface. This creates the cleanest appearance and most stable structure.

Step 10:

Apply 2½ cups (560g) of frosting evenly across the top of the cake, working from the center outward. Use the remaining frosting to cover the sides completely, using an offset spatula or bench scraper to smooth the surfaces. Make sure all areas are fully covered with an even layer of frosting.

Step 11:

This critical step transforms the texture of the cake. Wrap the entire cake with plastic wrap, pressing it directly against the frosting surface to create a complete seal that prevents air exposure. Refrigerate overnight (at least 8 hours). During this time, the cake layers and coconut will absorb moisture from the frosting, creating a pudding-like texture throughout.

Step 12:

One hour before serving, remove the cake from the refrigerator and unwrap it. Let it stand at room temperature to take the chill off. Because of the unique texture that develops, use a serrated knife with a gentle sawing motion to cut clean slices. Wipe the knife between cuts for the neatest presentation.

My grandmother first introduced me to ube desserts when I was a child, and the earthy-sweet flavor has always reminded me of family gatherings. What I love most about the ube in this recipe is how it transforms simple ingredients into something truly special, creating flavors that feel both comforting and exotic at the same time.

The Science Behind the Texture

The magic of this cake lies in its unique frosting method and overnight rest. Unlike traditional buttercream which creates a barrier, this sour cream and coconut mixture actively interacts with the cake layers during refrigeration. The sugar in the frosting draws moisture from the sour cream, creating a syrup that the shredded coconut and cake gradually absorb. This osmosis effect transforms what starts as separate components into a unified texture that's somewhere between cake, pudding, and coconut macaroon. The science explains why this cake improves with time—it's actually completing its final "cooking" phase in the refrigerator.

Make-Ahead and Storage Tips

This cake is the perfect make-ahead dessert, actually requiring overnight refrigeration to develop its intended character. You can prepare it up to three days before serving with excellent results. If you need to work even further ahead, the unfrosted cake layers can be wrapped tightly in plastic wrap and frozen for up to one month—just thaw completely before assembling. Once frosted and set, the cake will keep beautifully in the refrigerator for up to five days, though the texture is at its absolute peak between 24-72 hours after assembly. Always bring refrigerated slices to room temperature before serving for the fullest flavor experience.

Variations to Try

While the classic ube-coconut combination is magnificent on its own, this versatile recipe welcomes thoughtful variations. For a tropical twist, fold 1 cup of finely diced fresh mango into the frosting just before assembly—the bright acidity beautifully complements the sweet earthiness of the ube. You could also incorporate toasted macadamia nuts between the layers for added crunch and buttery flavor. For special occasions, consider garnishing the cake with edible flowers like pansies or violets that echo the purple hue of the cake itself. Some bakers in my circle have even experimented with replacing a quarter of the buttermilk with coconut milk to amplify the tropical notes throughout the cake layers, creating an even more cohesive flavor profile from center to edge.

Recipe FAQs

→ What is ube halaya and where can I find it?

Ube halaya is a sweet purple yam jam made from boiled and mashed purple yams with condensed milk and butter. You can find it in Asian grocery stores, particularly Filipino markets, or online specialty food retailers. Some stores sell it in jars labeled as 'ube jam' or 'purple yam jam'.

→ Can I make this cake without ube paste?

While ube paste enhances the purple color and flavor, you can omit it if unavailable. The cake will still get flavor from the ube halaya, though the color may be less vibrant. You can add a drop of purple food coloring as an alternative for visual impact.

→ Why does this cake need to be refrigerated overnight?

The overnight refrigeration is crucial for the coconut frosting to set properly. During this time, both the cake layers and coconut shreds absorb excess moisture from the frosting, transforming the texture and allowing flavors to meld. This creates the cake's unique consistency and taste.

→ Can I use sweetened coconut instead of unsweetened?

It's not recommended to substitute sweetened coconut in this recipe. The frosting already contains sugar, and using sweetened coconut would make it excessively sweet and alter the texture. Unsweetened coconut is key to achieving the proper balance of flavors.

→ How long can this cake be stored?

This ube coconut cake can be stored in the refrigerator for up to 4 days. Keep it wrapped in plastic that touches the frosting directly to prevent it from drying out. Always allow it to sit at room temperature for about an hour before serving for the best texture and flavor.

→ What type of neutral oil works best for this cake?

Vegetable oil, canola oil, or grapeseed oil all work well as neutral oils in this cake. These oils have minimal flavor, allowing the ube and coconut to shine through, while contributing to the cake's moisture and tender crumb.