• Prepare your pans and oven: Preheat your oven to 350°F (175°C). Grease and flour three 8×2 inch round cake pans, lining the bottoms with parchment paper circles for extra assurance.
• Mix dry ingredients: In a medium bowl, whisk together the cake flour, baking powder, baking soda, and salt. Set this dry mixture aside.
• Mix wet ingredients: In a separate bowl, combine buttermilk, vegetable oil, lime zest, and key lime juice. Set aside this liquid mixture.
• Cream butter and sugar: In the bowl of your mixer, cream the softened butter on medium speed until it becomes smooth. Gradually add in the sugar, continuing to mix for 3 to 5 minutes until the mixture turns light in color and achieves a fluffy texture.
• Incorporate eggs: Add the eggs one by one, ensuring each yolk is fully incorporated before adding the next.
• Combine flour and liquids: On low speed, alternately add the dry flour mixture and the buttermilk mixture to the creamed butter, beginning and ending with the dry ingredients. Do this in 5 steps: 3 parts dry, 2 parts wet. Be careful not to overmix—stop once the batter is just combined.
• Bake: Evenly distribute the batter into the prepared pans. Bake for 22 to 24 minutes, or until a toothpick inserted into the center of the cakes comes out clean or with a few crumbs clinging to it. Let the cakes cool in their pans for 10 minutes before turning them out onto a wire rack to cool completely.

For the Coconut Cream Cheese Frosting

• Prepare your equipment: Chill your mixing bowl and beaters in the freezer for 15 minutes (or 30 minutes if using the refrigerator).
• Whip the cream: Using a whisk attachment on your stand mixer or beaters on a hand mixer, whip the heavy cream until stiff peaks form. You’ll know it's ready when you lift the beaters, and the cream stands upright without collapsing. Place this whipped cream in the fridge to keep it cool while you continue.
• Mix cream cheese and sugar: In another bowl, beat the softened cream cheese, sifted powdered sugar, coconut extract, and key lime juice (if using) until perfectly smooth.
• Fold together: Gently fold the whipped cream into the cream cheese mixture until thoroughly combined. Cover the frosting and refrigerate. If you're using a piping bag and the frosting softens, simply place the bag in the refrigerator for a short time to firm it up.