Prepare the yellow boxed cake mix as directed on the package. Add an addition of vanilla with the rest of the ingredients to bump up the vanilla flavor.
Line 2 cupcake pans with liners. Fill with batter and bake as directed on the box.
Make the filling and frosting as the cupcakes are baking.
In a bowl add in the sweetened condensed milk and the preferred flavor of Kool-Aid Easy Mix. Mix with a spoon until incorporated.
When the cupcakes are done, start poking holes in the cupcakes while they're warm. I used a skewer and moved them around a little to make the holes slightly larger.
Once all the cupcakes are poked, add 1 teaspoon slowly on the top of each cupcake. This will prevent it from flowing over the edges. Push the filling around with the back of the measuring spoon.
In a large mixing bowl, add in the butter and vanilla. Mix on high until for about 30 seconds.
Add in the powdered sugar a cup at a time and mix on low.
Once the frosting gets too stiff (about 3 cups in) add the sweetened condensed milk. Mix on low until incorporated.
Beat on high for 2 minutes until the frosting is light and fluffy.
Remove about a third of the frosting and place it in a mixing bowl. Add in 1 and half tablespoon of the preferred flavored of Kool-Aid Easy Mix. Stir and taste. You can add the remaining flavoring, but it will thin it out a bit. Stir until incorporated.
Add in a corresponding gel paste food color to your frosting to brighten the color. Tropical and Cherry will use pink and grape will use voilet.
To stipe your piping bag, use a knife and shove the vanilla frosting down one side of the piping bag.
Add just enough of the flavored frosting to one side of the piping bag to have it go completely down the opposite side of the vanilla frosting. DO NOT use the same or more of the flavored frosting as you do the vanilla. **If you use too much of the flavored frosting at once because it will be a lot thinner and won't hold its shape if you're piping it.
Using a 1M tip, pipe swirls on the tops of your cooled cakes.