Prepare cake mix according to the package.
Preheat the oven to 350 degrees F.
Using a 24 holder mini muffin pan or cupcake pan, place your cones in each tin.
Place about 3 Tablespoons of cake batter into each of the cones, just below the inside rim. You can spoon the batter in or use a small ice cream scoop to be more accurate. Do not overfill. If you do, the batter will spill over while cooking and make the rims of the cones soggy. Each cone may bake up a little differently in shape but they will look great as soon as you frost them!
Bake them at 350 degrees F for 23 to 25 minutes or until a toothpick releases clean.
Allow them to cool completely.
While the ice cream cone cupcakes are cooling, you can make the buttercream.
In a large bowl or stand mixer fitted with a paddle attachment, cream butter on low speed until pale and creamy.
Slowly add in 3 cups of confectioners' sugar and 3 tbsp heavy cream a little at a time, alternating between each, while mixing on low over the course of about 3 minutes.
If your frosting needs a more stiff consistency, add remaining sugar. If your frosting needs to be thinned out, add the remaining cream.
Add vanilla and salt.
Beat on medium-high for about 2 to 3 minutes until the frosting is light and fluffy.
If you want to make multiple colors of frosting, just separate your buttercream into individual bowls and use food coloring to make whatever color your heart desires! If you want to make chocolate buttercream, add ½ cup of unsweetened cocoa powder and 2 tablespoons of vanilla extract and fold in with a spatula until incorporated.
You can pipe the frosting into a swirl (using a Wilton 2D tip and piping bag) OR you can quickly just spread your frosting on top of each cupcake with a knife - kiddos will eat them either way!
Toss some sprinkles on top for a fun garnish.