Preparation

Step 1: Prepare the Cake Batter

1. Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans or line them with parchment paper.
2. In a medium bowl, whisk together the all-purpose flour, baking powder, and salt. Set aside.
3. In a large mixing bowl, beat the butter and sugar together until light and fluffy, about 3-5 minutes.
4. Add the eggs one at a time, mixing well after each addition.
5. Stir in the key lime zest and vanilla extract.
6. Alternate adding the dry ingredients and buttermilk, beginning and ending with the flour mixture. Mix until just combined.
7. Gently fold in the key lime juice, ensuring the batter is smooth and well incorporated.

Step 2: Bake the Cake

1. Divide the batter evenly between the prepared cake pans.
2. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
3. Remove from the oven and let the cakes cool in the pans for 10 minutes.
4. Transfer to a wire rack to cool completely before frosting.

Step 3: Prepare the Key Lime Cream Cheese Frosting

1. In a large mixing bowl, beat the cream cheese and butter together until smooth and creamy.
2. Gradually add the powdered sugar, mixing well after each addition.
3. Stir in the key lime juice, zest, and vanilla extract. Mix until the frosting is smooth and fluffy.

Step 4: Assemble the Cake

1. Place one cake layer on a serving plate and spread a generous amount of frosting on top.
2. Place the second cake layer on top and spread frosting over the entire cake, including the sides.
3. Use a spatula to create decorative swirls or smooth out the frosting for a polished look.

Step 5: Garnish and Serve

1. Garnish the cake with additional key lime zest for extra flavor and visual appeal.
2. Refrigerate for at least 30 minutes before slicing to allow the frosting to set.