Preheat the oven to 350°F, and line two cupcake pans with liners.
In a large mixing bowl, combine cake mix, vanilla pudding, eggs, sour cream, oil, and water. Use a spatula to fold 1 cup Fruity Pebbles into cupcake batter.
16.25 ounces white cake mix, 3.4 ounce instant vanilla pudding, 3 large eggs, ¾ cup sour cream, ¾ cup vegetable oil, ½ cup water
Use a measuring cup or scoop to fill the cupcake liners about ¼ to ½ way full.
Baked for 15 to 20 minutes until a toothpick inserted in the center comes about clean. Transfer the cupcakes to a wire rack to cool. Allow the cupcakes to cool completely before frosting.
To Make the Key Lime Buttercream Icing
In a stand mixer or large mixing bowl combine softened butter, powdered sugar, milk, and key lime juice. Start with less milk and more to achieve the desired consistency.
1 cup unsalted butter, 4 cups powdered sugar, 4 to 6 tablespoons milk, 1 tablespoon key lime juice
Once cupcakes have cooled to room temperature, frost the cupcakes and sprinkle the remaining ½ cup of cereal on top of each cupcake as garnish.
Notes
*The calories listed are an approximation based on the ingredients in the recipe card and a serving size of 1 cupcake. Actual calories will vary.*For more information, tips, and answers to frequently asked questions, please refer to the post.