Start by zesting and then juicing enough key limes for both the cupcakes and the frosting and setting them aside.

Preheat your oven to 350°F / 180°C and line a standard muffin tin with paper or silicon cupcake liners and set aside.

In a mixing bowl, add 1 ½ cups cake flour, 1 teaspoon baking powder, ¼ teaspoon baking soda, and ½ teaspoon salt and then whisk until fully combined, then set aside.

In the bowl of a stand mixer, or a large mixing bowl if using a hand mixer, add a ¼ cup softened unsalted butter and 1 cup white sugar and cream together on medium until light and fluffy, about 3-5 minutes.

Once the butter and sugar are creamed, add ¼ cup vegetable oil, ½ cup sour cream, 2 tablespoons key lime zest, ¼ cup key lime juice, and ½ teaspoon vanilla extract. Mix at low speed for about a minute or so just to combine. Now add 1 large egg and 1 large egg yolk, one at a time, and mix on medium low speed until there’s no obvious streaks of egg remaining.

Now add the dry mix into the wet mix, a little at a time, and mix at a low speed. Add the rest of the dry mixture in 1-2 more increments until just combined.

Finally, mix in 1 cup sweetened, shredded coconut and fold into the batter with a spatula or Danish dough whisk.

Scoop the batter into the lined muffin tin, filling the liners about ⅔ or so full, keeping them as even as you can until you’ve used all the batter.

Place on the middle rack of your oven and bake for 16-20 minutes, until an inserted toothpick comes out mostly clean. Remove from the oven and allow them to finish cooking and setting up in the muffin tin for 5 minutes or so. Once cool enough to remove, transfer to a cooling rack to cool completely before frosting them.

While the cupcakes are cooking, you can start making the frosting.

In the cleaned bowl of a stand mixer with the whisk attachment, or in a large mixing bowl if using a hand mixer, add 6 tablespoons softened butter and half of the 4 cups powdered sugar. Mix at low speed until mostly combined, then add the rest of the sugar. Continue mixing at low speed for a minute, then raise the speed to medium and cream together until light and fluffy, about 4-5 minutes.

Add 8-ounces cream cheese and continue mixing until mostly combined, about 2-3 minutes longer. Finally, add 2 teaspoons key lime zest, 2 tablespoons key lime juice, ½ teaspoon vanilla extract, and ½ teaspoon coconut extract. Mix at medium speed until fully combined and smooth. Cover and refrigerate until ready to use.

Once the cupcakes have fully cooled and the cream cheese frosting has set up and chilled, you can decorate the cupcakes.

If you’re using toasted coconut, toast it while waiting for the cupcakes to cool so that it has time to cool completely as well. In a small pan set over medium low heat, pour in a ¼ cup of the sweetened coconut shreds and shake to spread out evenly.

Give the pan a shake and toss occasionally. Once it starts to brow, it will finish quickly, so keep an eye on the pan and shake and toss more frequently. When it begins turning golden brown color, turn off the heat and pour the coconut flakes into a bowl to stop the cooking process. Set aside to finish cooling completely before using.

Fill a piping bag with some frosting and pipe from the outside into the middle of the cupcake in a closing circle, going up and making another circle towards the center. For reference, I used a large, Wilton 8B piping tip. Alternatively, use a knife and just smear on a thick layer of frosting. Decorate with key lime slices, toasted coconut, sprinkles, sanding sugar, or more zest and enjoy.