Thai Coconut Milk Crumb Cake with Lime Zest
A tender, moist coffee cake infused with coconut milk and bright lime zest, topped with a buttery coconut crumb streusel. The subtle tropical flavors of Thailand—coconut, lime, and a whisper of salt—make this an elegant yet comforting breakfast or afternoon treat. The crumb topping adds textural contrast and bakes up golden and crispy.
- Prep
- 15 min
- Cook
- 35 min
- Wait
- 15 min
- Total
- 1 hr 5 min
- Makes
- 1 cake (8 slices)
Steps
Before you start
- Preheat your oven to 350°F (175°C) and position a rack in the center
- Line the bottom of a 9-inch (23 cm) round cake pan with parchment paper and butter the sides
- Bring the eggs, butter, and sour cream to room temperature (about 1 hour ahead, or place in warm water for 10 minutes)
- Zest the limes before juicing them (you need the zest for the batter and crumb topping)
Make the crumb topping
- In a medium bowl, combine the cold butter cubes, flour, brown sugar, shredded coconut, lime zest, and salt.
- Using your fingertips or two forks, work the butter into the dry ingredients until the mixture resembles coarse breadcrumbs with pea-sized pieces of butter visible.
- Do not overmix.
- Set aside until ready to use.
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Ready when: mixture resembles coarse breadcrumbs with visible pea-sized butter pieces
Tip: Keep the butter as cold as possible for a crumbly texture. If your kitchen is warm, chill the mixture for 5 minutes before using.
Cream butter and sugar
- In a large mixing bowl, beat the softened butter and granulated sugar together with an electric mixer on medium speed for 3–4 minutes, until the mixture is pale, fluffy, and noticeably lighter in color.
- Scrape down the bowl as needed.
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Ready when: mixture is pale, fluffy, and increased in volume
Tip: This incorporates air into the batter, giving the cake a tender crumb. Do not skip this step.
Add eggs and lime zest
- Add the eggs one at a time, beating well after each addition (about 1 minute per egg).
- Add the lime zest and beat until fully incorporated, about 1 minute.
- The batter should look smooth and creamy.
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Ready when: batter is smooth, creamy, and bright green-tinged from lime zest
Tip: Adding eggs slowly prevents the batter from curdling and ensures a smooth final texture.
Combine wet ingredients
- In a small bowl, whisk together the sour cream and coconut milk until smooth and fully combined.
- The mixture may look slightly curdled at first, but stirring vigorously will combine it.
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Ready when: liquid is smooth and homogeneous, coconut cream fully blended
Tip: Stirring well ensures the coconut milk disperses evenly throughout the batter for consistent flavor in every slice.
Mix dry ingredients
- In another bowl, whisk together the flour, baking powder, and salt.
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Ready when: dry ingredients are evenly combined with no lumps
Tip: Whisking the dry ingredients prevents pockets of baking powder that could create an uneven rise.
Alternate flour and wet ingredients
- Add the dry ingredients and the sour cream–coconut milk mixture to the butter mixture in three alternating additions, beginning and ending with the dry ingredients.
- Mix on low speed after each addition just until combined.
- After the final addition of flour, mix for no more than 10 seconds total.
- Do not overmix.
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Ready when: batter is smooth with no streaks of flour, slightly thicker than pancake batter
Tip: Overmixing develops gluten and produces a tough, dense cake. Stop as soon as the flour disappears.
Fill the pan and top with crumbs
- Pour the batter into the prepared 9-inch cake pan and smooth the top with a spatula.
- Evenly distribute the crumb topping over the batter, gently pressing it down so it adheres but does not compress into a solid layer.
- Leave some crumbs loose for textural appeal.
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Ready when: crumb topping is evenly distributed and lightly adheres to the batter
Tip: Don't press the topping too firmly, or it will bake into a hard crust rather than remaining crumbly.
Bake the cakeOven 350°F / 175°C
- Bake in the preheated 350°F (175°C) oven for 32–37 minutes, until a toothpick or cake tester inserted into the cake (avoiding the crumb topping) comes out clean or with just a few moist crumbs.
- The crumb topping should be golden brown.
- If the topping is browning too quickly, loosely tent the cake with aluminum foil after 25 minutes.
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Ready when: toothpick inserted into cake comes out clean or with just a few moist crumbs; crumb topping is golden brown
Tip: Overbaking dries out the cake. Test it at 32 minutes; it may be done earlier depending on your oven.
Cool and serve
- Allow the cake to cool in the pan for 15 minutes.
- Run a thin knife around the edges to loosen it, then invert onto a wire rack or serving plate.
- The cake can be served warm or at room temperature.
- Slice into 8 equal pieces.
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Ready when: cake has set enough to hold its shape when turned out
Tip: Cooling for 15 minutes allows the structure to set without drying the cake out. Serve slightly warm for the best texture and flavor.
Optional: Lime glaze
- For extra brightness, you may drizzle a simple lime glaze over cooled slices: whisk together 0.5 cup powdered sugar, 1 tablespoon fresh lime juice, and 0.5 teaspoon lime zest until smooth.
- Drizzle lightly over each slice just before serving.
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Tip: The glaze can be made ahead and stored in an airtight container for up to 2 days.
Store leftovers
- Cover leftover cake loosely with plastic wrap or store in an airtight container.
Good to know
Tips
- Room temperature eggs and butter incorporate more easily into the batter and produce a lighter, more tender cake. Plan ahead to remove them from the fridge 1 hour before baking.
- For the freshest lime zest, use a Microplane or fine zester rather than a box grater, which can bruise the lime oils and make the zest bitter.
- If you don't have unsweetened coconut milk, use lite (reduced-fat) coconut milk, but avoid sweetened cream of coconut, which will make the cake overly sweet and oily.
- Coconut milk varies in richness by brand; if yours seems very thick, stir well or add an extra 1–2 tablespoons of milk or sour cream to ensure the batter is moist but not runny.
Make ahead
The crumb topping can be made up to 1 day ahead and stored in an airtight container in the refrigerator. The finished cake is best served the day it is baked, but see Storage for multi-day keeping.
Storage & reheating
Room temperature (covered loosely): up to 2 days. Refrigerator (in an airtight container): up to 4 days. Freeze (wrapped tightly in plastic wrap and foil): up to 2 months. Thaw at room temperature for 2–3 hours or in the refrigerator overnight. Serve at room temperature or warm gently in a 300°F (150°C) oven for 5–8 minutes.
Substitutions
- sour cream → Greek yogurt (plain, full-fat). Use the same amount. It will yield a slightly more tender crumb and a subtly tangier flavor.
- unsweetened coconut milk (canned) → heavy cream or whole milk. Use the same amount. You will lose the coconut flavor, but the cake will still be moist and delicious.
- unsweetened shredded coconut → toasted chopped macadamia nuts or sliced almonds. Use the same amount. Toast nuts lightly before adding to the crumb topping for deeper flavor.
- lime zest, finely grated → lemon zest. Use the same amount. Lemon will give a brighter, more acidic note; reduce sugar in the crumb topping by 1 tablespoon if preferred.
