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Be sure to have this key lime cake in your cake rotation: It’s perfectly moist, slightly sweet, and just tart enough to bring back memories of key lime pie on grandma’s porch. This cake is sure to become one of your summer faves, too.
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Sugar Free Key Lime Cake
I love an ultra-rich, maple-filled, chocolate-doused, cherry-topped dessert but sometimes I want something more refreshing, citrusy, and lower in sugar! Enter this easy sheet cake recipe – a Key Lime Cake with lower added sugar!
Why You’ll Love This Recipe
- With low-sugar, a light consistency, and the refreshing flavor of key lime, this dessert makes for the perfect treat that won’t weigh you down in the heat of the summer.
- Perfect for all summer occasions, including pool parties, barbecues, and Fourth of July get-togethers!
- Vegetable oil – Instead of butter this cake uses oil to keep it nice and moist. Melted butter can be substituted.
- Sweetener Sugar Blend – I used a Splenda sugar for baking, which is a combination of sugar and sweetener. You can any brand (Truvia also makes it).
- Key lime juice – While I usually recommend fresh lime juice, key limes are so tiny and it’s hard to juice them, so you can use a bottle of key lime juice if you prefer.
- Lime zest – Don’t skip this – all that lime flavor comes from this.
- Heavy whipping cream – for the frosting we’re making a homemade whipped cream.
How to Make Key Lime Cake
- Preheat: With either butter and flour or nonstick cooking spray, prepare a 9” square pan. Preheat your oven to 350°F.
- Combine ingredients: In a medium bowl, whisk together baking powder, flour, and salt. In a separate, larger bowl, add sweetener and oil and mix together with a hand or stand mixer. Beat until the mixture becomes thick and yellow. Begin adding eggs to the bowl one at a time, beating the mixture after each egg is added. Then, mix in the lime juice, zest, and vanilla extract. Finally, add the flour mixture and milk alternately, starting and ending with the flour. Just be sure not to overmix.
- Bake: Pour the batter into the prepared pan and bake it for 25 to 35 minutes. You’ll know it’s done when you can stick a toothpick in the center that comes out clean.
- Make glaze: As the cake bakes, use a small pan to heat the lime juice and sweetener over medium-heat. Heat until the mixture begins to boil, stirring to ensure that the sugar fully dissolves. Once dissolved, remove the glaze from heat and cool until the cake is finished baking.
- Glaze cake: When the cake has finished baking, use a fork to poke holes all over the top of the cake. Pour the glaze you’ve made all over the top of the cake, then allow it to cool completely.
- Make frosting: To make the frosting, you’ll want to beat cold heavy whipping cream with a hand or stand mixer until stiff peaks of whipped cream form. As they form, add the sweetener and lime zest.
- Frost and serve: Frost the cake with the lime whipped cream and garnish with more lime zest, or garnish with thinly sliced limes.
- If you want to use regular sugar, just swap out the stevia for ½ cup sugar. This will result in a cake slightly fluffier than if made with sweetener.
- You can easily make this cake ahead, but you’ll want to hold off on the whipped cream frosting until just before serving.
- Feel free to make whipped cream frosting or even a vanilla buttercream for this cake instead!
Yes, you can substitute the stevia for regular sugar. In this recipe, you can use a ½ cup of sugar in place of the stevia.
Sort of – it’s recommended that when substituting key lime juice for lime juice, you actually should use ½ lime juice and ½ lemon juice.
If you’ve already frosted the cake with whipped cream, yes, it needs to be stored in the fridge. If you haven’t frosted your cake yet, feel free to store cooled cake slices on the counter after wrapping them in plastic wrap.
Yes, you can freeze key lime cake in a ziplock bag for up to two months.
Key Lime Cake
- 1 ½ cups (186g) all-purpose flour
- 1 teaspoon baking powder
- ½ teaspoon salt
- ½ cup (118ml) vegetable oil
- ½ cup SPLENDA® Naturals Sugar & Stevia Sweetener Blend
- 3 large eggs
- 1 tablespoon vanilla extract
- ¼ cup (59ml) key lime juice
- 1 tablespoon lime zest from about 1 large or 2 medium limes
- ½ cup (118ml) milk
- 3 ounces key lime juice about 6 tablespoons
- 2 tablespoons SPLENDA Naturals Sugar & Stevia Sweetener Blend
Whipped Cream Topping:
- 1 cup heavy whipping cream
- 1 tablespoon SPLENDA Naturals Sugar & Stevia Sweetener Blend
- Zest of one small or half a large lime
- Additional zest and/or lime slices for garnish (optional)
- Preheat oven to 350°F. Spray a 9” square pan with nonstick cooking spray, or butter and flour it.
- Whisk flour, baking powder, and salt in a medium bowl.
- Add oil and SPLENDA to a large bowl and with hand mixer or stand mixer, until thick and yellow. Add eggs one at at time, beating after each addition. Beat in vanilla extract, lime juice, and zest.
- Add the flour mixture and milk alternately, starting and ending with the flour. Don’t over mix! Pour batter into prepared pan.
- Bake for 25-35 minutes until a toothpick comes out clean. Note: the cake will look a bit different when done than a normal cake does; this is because of the sugar substitute. Use the toothpick to test doneness.
- While the cake is baking, make the glaze by heating the lime juice and SPLENDA in a small pan over medium heat. Cook just until it starts to boil, stirring to make sure the sugar is dissolved. Remove from heat and cool until the cake is done.
- When the cake comes out of the oven, poke several tiny holes all over the top of the cake with a toothpick. Pour the glaze over the top. Cool completely before frosting.
- Make the whipped cream frosting: beat cold heavy whipping cream until stiff peaks form, slowly adding the SPLENDA and lime zest during mixing. Frost the top of the cake and sprinkle with more lime zest and/or lime slices.
- Best served the day it’s frosted with the whipped cream, but the cake can be made up to 24 hours in advance (cover cooled cake tightly with plastic wrap and store on the counter). Frost just before serving.
- To use regular sugar: swap 1/2 cup granulated sugar
Other Key Lime Recipes
Last Updated on April 17, 2023
Can this be made without milk and additional juice instead?
Also, if made with real sugar, how much should go in the cake mix? The recipe says 1 cup, but a response in the Comments says 1 1/4 cups.
Could this be made in two round cake pans instead of the rectangular pan?
It’s like SPRING time on a plate. I served this at a family brunch and everyone enjoyed it so much!
Hi, I just made this recipe and though it has good taste the cake came out flat, did not rise. Could it be because I used lactose free milk? If not, why could it be?