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    Home » Recipes » Box Cake Mix Desserts

    Quick Key Lime Dump Cake

    Published: Jun 21, 2026 by Andrea · This post may contain affiliate links · Leave a Comment

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    This quick key lime dump cake is an easy dessert with only 5 simple ingredients and in less than 30 minutes! It's incredibly delicious with its refreshing, tart, and citrusy flavour and buttery crumble topping!

    Key lime dump cake in a white baking dish topped with cool whip and lime twists.
    Jump to:
    • Ingredients
    • Step-by-Step Instructions
    • Storage
    • Related Recipes
    • 📖 Recipe
    • 💬 Comments

    I was skeptical the first time I decided to make this recipe. Something about citrusy flavours like lime baking in the oven has never made sense to me. That's why I make other citrusy desserts no bake most of the time (like this no bake key lime pie and this no bake condensed milk lemon pie).

    This key lime dump cake proved me wrong though. It's such a crowd pleaser at any occasion I bring it to! Everyone loves the refreshing and bright lime flavour and the rich and comforting texture it has (similar to a cobbler kinda, just without the fruit!)

    Ingredients

    • Condensed Milk
    • Lime Juice (this recipe uses regular limes because they're generally more accessible at the grocery store, but feel free to use key limes if you have access to them. You can also use bottled lime juice but it likely won't taste as fresh)
    • Sour Cream
    • Boxed Vanilla Cake Mix (white cake mix and yellow cake mix also work and taste great as an alternative)
    • Butter

    See the recipe card below for the ingredient measurements. 

    Step-by-Step Instructions

    Step 1 - Prepare: Preheat the oven to 350°F and grease a 9x13 baking dish with cooking spray.

    Step 2 - Make the filling: To a mixing bowl, whisk the condensed milk, lime zest, lime juice, and sour cream together and pour into the prepared baking dish.

    Condensed milk, lime zest and juice, and sour cream mixed together in a bowl.
    Key lime filling in a white baking dish.

    Step 3 - Making the topping: In a separate bowl, combine the melted butter and cake mix and mix with a fork until a crumbly texture is formed. Sprinkle the crumble over the filling.

    Cake mix and melted butter combined into a crumble in a bowl.
    Crumble sprinkled over the key lime filling in the baking dish.

    Step 4 - Bake: Bake uncovered on the middle rack for 20-22 minutes, until the crumble is slightly golden. Serve warm with vanilla ice cream or room temperature with whipped cream or Cool Whip.

    Baked key lime dump cake from the oven.

    Storage

    Store in the fridge covered tightly in plastic wrap for up to one week.

    Piece of key lime dump cake in a bowl topped with cool whip and a lime wedge.

    Related Recipes

    If you like lime desserts, then you should also try my no bake key lime pie!

    Some other easy dump cakes you might like are this chocolate pudding dump cake and this chocolate peanut butter dump cake.

    Print

    📖 Recipe

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    Key lime dump cake in a white baking dish topped with cool whip and lime twists.

    Quick Key Lime Dump Cake


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    • Author: Andrea
    • Total Time: 30 minutes
    • Yield: 8
    • Diet: Vegetarian
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    Description

    This quick key lime dump cake is easy to make and incredibly tasty with its refreshing lime flavour!


    Ingredients

    Units
    • Condensed Milk: two cans (14 oz each)
    • Limes: 6 (zest ½ of them and juice them all)
    • Sour Cream: ½ cup
    • Vanilla Cake Mix: one box (15.25 oz)
    • Butter: ½ cup, melted


    Instructions

    1. Prepare: Preheat the oven to 350°F and grease a 9x13 baking dish with cooking spray.
    2. Make the filling: To a mixing bowl, whisk the condensed milk, lime zest, lime juice, and sour cream together and pour into the prepared baking dish.
    3. Making the topping: In a separate bowl, combine the melted butter and cake mix and mix with a fork until a crumbly texture is formed. Sprinkle the crumble over the filling.
    4. Bake: Bake uncovered on the middle rack for 20-22 minutes, until the crumble is slightly golden. Serve warm with vanilla ice cream or room temperature with whipped cream or Cool Whip.

    Equipment

    Image of 9x13 Baking Dish

    9x13 Baking Dish

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    Image of Whisk

    Whisk

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    Notes

    Another option for the filling is to use key lime pie instant pudding.

    Nutrition facts are for informational purposes only. We are not responsible for any errors. We have tested the recipe for accuracy, but your results may vary. Please note that this is not medical or nutrition advice. Seek advice from a licensed professional if you need advice. We are not liable for any damages caused by your use of this content.

    • Prep Time: 10 minutes
    • Cook Time: 20 minutes
    • Category: Dessert
    • Method: Baking
    • Cuisine: American

    Did you make this recipe?

    I'd love to hear from you in the comment section below!

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    Recipe rating 5 Stars 4 Stars 3 Stars 2 Stars 1 Star

    Food blogger holding a tray of muffins.

    Hi & Welcome!

    I'm Andrea, the recipe developer, food photographer, blogger, and creator of Cup of Flour. Here I share all my tried and true recipes, all made with basic ingredients. I'm so happy you're here!

    About Andrea →

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