Use one box of white cake mix. Add three eggs, ⅓ cup of vegetable oil, and ¼ cup of fresh key lime juice, ¾ cup of water and the zest of 1-3 key limes depending on how strong you’d like the key lime flavor to be. It's a good idea not to grate too much of the white part (lime pith) because it will taste more bitter than the green outer layer.

Add your wet ingredients to your dry ingredients in a medium bowl and mix them until they're smooth. You can use a spoon or ice cream scoop to fill your paper liners and set them in muffin cups or a cupcake pan. Fill each cupcake liner 3/4 full.

Bake the lime cupcakes at 350 Fahrenheit for 16 minutes or until they spring back when lightly touched. Let them cool on a wire rack.

Mix one 3 oz box of Lime Jello (85 grams) with ¼ cup of boiling water until all the crystals are dissolved. Then add ⅓ cup of ice cubes (or ¼ cup of cold water) and stir. Set aside your Jello mixture until it’s cooled to room temperature.

Take two cups of vanilla fat-free yogurt, and whisk it using an electric mixer or for 2-5 minutes at a medium-high speed until it’s increased in size and starting to look bubbly. If you use other types of yogurt, it may end up being quite a bit thicker.

Add the room-temperature Jello mixture to the vanilla yogurt and whisk it together for another 5-7 minutes until it’s full of airy bubbles.

Refrigerate the lime fluff mixture for 2 hours until it’s cooled and set completely.

In a large bowl, put 4 cups of powdered sugar, one cup of room temperature unsalted butter, 1 teaspoon of pure vanilla extract, the zest and juice of one lime and mix them together with a hand mixer or stand mixer until your buttercream frosting is smooth. If you need more liquid, you can add 1 tablespoon of milk or heavy cream. If your tangy lime buttercream frosting is too liquidy, add more powdered sugar. Use room temperature ingredients for best results. Cold butter will be too hard to blend. Start at a low speed until all your ingredients are incorporated, then switch to a medium speed.

Take ¼ cup of your lime buttercream and add green food coloring to it. Then put a Wilton 4B open star piping tip inside a piping bag and add a streak of green frosting to the inside. Fill the rest of your piping bag with white frosting. This will give your icing a streak of green when you start decorating.

Once your cupcakes have completely cooled to room temperature, use a sharp knife to cut a small hole in the top of each cupcake.

Put a spoonful of the cooled lime fluff into a piping bag and cut off the tip. Pipe lime fluff into the hole in the cupcake.

Pipe lime buttercream on top of your cupcake and then top it with a sliver of lime wedge as a garnish. Keep your cupcakes in the fridge until about an hour before you’re ready to serve them.