This key lime pie cake is a one layer key lime cake (it has lime zest and key lime juice in the batter!). It is topped with key lime cream cheese frosting and a graham cracker crumble. It tastes just like key lime pie in a cake!

This key lime pie cake is your favorite pie in cake form! With key lime flavor throughout the whole cake and frosting it is SO good with every bite. With a graham cracker crumble for a perfect crunch and extra lime on top of the cake it is also easy to decorate and looks great on the dessert table of any party. It is perfect at any special occasions or birthday party with lime fans.
For other fruity dessert recipes, try Strawberry Cookies, Lemon Bar Cupcakes, and Strawberry Brownies.
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Why This Recipe Works
- Key lime flavor- This moist key lime cake has all of flavor of a classic key lime pie in a delicious cake!
- Moist cake- This cake is moist and tender. It has the perfect texture.
- Easy recipe- This easy key lime pie cake recipe is only a single layer and is broken down into simple steps.
Ingredient Notes
Here are some notes on the ingredients. For a full list of ingredients, check out the recipe card below.
- Unsalted butter- Pull this out 2 hours before baking.
- Oil- Use canola oil, vegetable oil, or olive oil.
- Eggs- Pull the large eggs out 2 hours before baking to get room temperature eggs.
- Buttermilk- Use full fat or reduced fat buttermilk. Pull this out 2 hours before baking.
- Cream Cheese- Pull this out 2 hours before baking.
- Powdered sugar- Make sure this is sifted to avoid gritty frosting.
- Key lime juice- I used a bottle of pre-juiced lime juice as juice directly from the key limes is a bit more bitter.
- Food dye- Cheap food coloring needs more to get a good color and can affect the taste. I recommend a gel food coloring. I used Americolor.
Step By Step Instructions - Cake
Here is how to make and bake this key lime pie cake. This recipe uses an electric mixer. You can use a stand mixer with paddle attachment or a powerful hand mixer.
STEP 1: Prep. Preheat the oven to 350°F. Then, spray a 9X9 inch square pan with nonstick baking spray. Line the bottom of the baking pan with parchment paper and spray it again.
STEP 2: Dry ingredients. Sift together the all purpose flour, baking powder, baking soda, and salt in a medium bowl.
STEP 3: Beat butter, oil, and sugar. In a separate bowl, use your mixer to beat the butter, oil, and sugar on high speed for 3 minutes.
STEP 4: Wet ingredients. Add the key lime zest, key lime juice, vanilla extract, sour cream, and eggs to the butter mixture. Mix it on medium speed until it is combined.
STEP 5: Combine. Add ⅓rd of the flour mixture and half of the buttermilk and mix it in on low speed. Add another ⅓rd of the dry ingredients and mix it in on low speed. Finally, add the remaining flour mixture and mix it in.
STEP 6: Bake. Pour the batter in the prepared pan. Bake it for 30-33 minutes. It is done when a toothpick inserted in the middle of the cake comes out clean. Start the crumble while the cake is baking.
STEP 7: Cool. Let the cake cool in the hot pan for 10 minutes. Then, transfer it to a cooling rack.
Step By Step Instructions - Crumble and Frosting
Here is how to make and bake the graham cracker crumble and key lime cream cheese frosting.
STEP 1: Mix crumble. Mix the graham cracker crumbs, brown sugar, cinnamon, and melted butter together. Let it cool in the fridge while the cake is baking.
STEP 2: Prep. Once chilled, spray a cookie sheet with nonstick baking spray. Then, spread the crumble in an even layer over the cookie sheet.
STEP 3: Bake crumble. Bake it for 5 minutes at 350°F. As soon as it is done baking use a rubber spatula to mix the crumble up. Then, let it cool completely.
STEP 4: Sift sugar. Sift the powdered sugar for the frosting into a large bowl and set it aside.
STEP 5: Beat butter and cream cheese. Beat the butter and cream cheese on high speed in your mixer for 2 minutes.
STEP 6: Combine. Add half of the powdered sugar to the butter mixture and mix it in on low speed. Add the rest of the powdered sugar and combine it on low speed. Next, add the vanilla extract, lime zest, key lime juice, and salt. Combine it with the mixer on medium speed.
STEP 7: Green dye. Add a very very small amount of green food dye gel. Only add enough for a pastel green, not a heavily saturated green.
STEP 8: Frost cake. Spread an even layer of frosting over the cake. Then, add the crumbles and extra lime slices to decorate.
Expert Baking Tips
- Properly measure the flour- Make sure the flour is spooned and leveled. If you stick the measuring cup directly into the flour, it will compact the flour. Compacted flour can cause the cake to be dry.
- To easily remove the cake from the pan, make sure to first spray the pan with baking nonstick spray. Then, line bottom with parchment paper and spray it again to make sure that the paper does not stick to the bottom of the cake too much. If you miss any spots with the spray they can stick and tear the cake so be thorough.
- For high altitude baking add 2 tablespoon of flour to the cake batter.
FAQ
Yes you can make the cake ahead of time! Once the cake layer is done cooling, wrap tightly in plastic wrap. Then, freeze up to 30 days. Pull it out 1 hour before decorating.
Yes you can. An 8X8 pan will make a thicker cake. A 9in round pan will also work, but will be slightly thicker than a 9 in square as well.
Yes it can! This recipe will make roughly 12 cupcakes.
Storing and Freezing
Store this key lime pie cake in an airtight container like a cake carrier. Store in the fridge up to 5 days.
Freezing
You can freeze the key lime pie cake in individual slices. Place the cake slices in an airtight container and freeze up to 30 days.
Other Cake Recipes To Try
Make sure to leave a STAR REVIEW if you loved this recipe! Make sure to tag me on Instagram @stephaniesweettreats. To get more ideas follow me on Pinterest.
📖 Recipe
Key Lime Pie Cake
Ingredients
Key Lime Cake
- 2 ¼ cups All-purpose flour
- 2 ½ teaspoon Baking powder
- ¼ teaspoon Baking soda
- ½ teaspoon Salt
- ½ cup Unsalted butter room temperature
- 3 tablespoon Oil canola or vegetable
- 1 cup White granulated sugar
- 1 teaspoon Pure vanilla extract
- Zest of 3 limes
- ⅛ cup Key lime juice Use key lime juice in the bottle
- ⅛ cup Sour cream room temperature
- 3 Large eggs room temperature
- ¾ cup Buttermilk room temperature
Graham Cracker Crumble
- ½ cup Graham cracker crumbs medium and small crumbs
- ⅛ cup Brown sugar packed light or dark
- ½ teaspoon Ground cinnamon
- 3 tablespoon Unsalted butter melted
Key Lime Cream Cheese Frosting
- ½ cup Unsalted butter room temperature
- 8 oz Cream cheese room temperature
- 2 cups Powdered sugar sifted
- Zest of 2 limes
- 1 teaspoon Pure vanilla extract
- 1 tablespoon Key lime juice
- ¼ teaspoon Salt
- Green gel food coloring
Instructions
Key Lime Cake
- Preheat oven to 350°F. Spray a 9X9-inch square pan with baking nonstick spray. Line the bottom of the pan with parchment paper. Spray again.
- In a medium bowl, sift the flour, baking powder, baking soda, and salt. Set aside.2 ¼ cups All-purpose flour, 2 ½ teaspoon Baking powder, ¼ teaspoon Baking soda, ½ teaspoon Salt
- Using a mixer, beat the butter, oil, and sugar on high speed for 3 minutes.½ cup Unsalted butter, 3 tablespoon Oil, 1 cup White granulated sugar
- Then, add the zest of the key limes, key lime juice, vanilla extract, sour cream, and eggs. Mix on medium until combined.1 teaspoon Pure vanilla extract, Zest of 3 limes, ⅛ cup Key lime juice, ⅛ cup Sour cream, 3 Large eggs
- Add ⅓rd of the dry ingredients and half of the buttermilk and mix on low speed. Add another ⅓rd of the dry ingredients and the rest of the buttermilk. Then, finish with the rest of the dry ingredients.¾ cup Buttermilk
- Pour into the pan. Bake for 30-33 minutes until a toothpick inserted comes out clean.
- Let the cake sit in the hot pan for 10 minutes. Then, transfer to a cooling rack. Cool completely before decorating.
Graham Cracker Crumble
- Start making the crumble while the cake layers are in the oven.
- Mix the graham cracker crumbs, brown sugar, cinnamon, and melted butter together. Place in the fridge while cake is baking.½ cup Graham cracker crumbs, ⅛ cup Brown sugar, ½ teaspoon Ground cinnamon, 3 tablespoon Unsalted butter
- Spray a cookie sheet with baking spray. Spread the crumble over the cookie sheet.
- Bake for 5 minutes at 350°F. Immediately after baking, use a rubber spatula to mix the crumble up. Let it cool completely.
Key Lime Cream Cheese Frosting
- In a large bowl, sift the powdered sugar. Set aside.2 cups Powdered sugar
- Using a mixer, beat the butter and cream cheese on high speed for 2 minutes.½ cup Unsalted butter, 8 oz Cream cheese
- Add in half of the powdered sugar and mix on low speed until combined. Repeat with the rest of the powdered sugar. Add in the vanilla, lime zest, key lime juice, and salt. Mix on medium speed until combined.Zest of 2 limes, 1 teaspoon Pure vanilla extract, 1 tablespoon Key lime juice, ¼ teaspoon Salt
- Add a very very small amount green gel food dye. You want a small amount so it becomes a pastel green color vs a very saturated green.Green gel food coloring
- Spread the frosting over the cake. Top with the crumbles and extra slices of lime for decoration.
Kimberly Hashagen says
Question: the body of story says 2 tbs of extra flour. The recipe says 3 tbs. Could you clarify which is correct ? Thank you. I can’t wait to try this !!!
Stephanie Rutherford says
Do 3 TBSP