Bake your favorite cupcake batter according to its recipe, then let the cupcakes cool fully on a wire rack. This step really can't be rushed, since warm cupcakes will melt your frosting the second it touches them.
Beat the softened butter on medium speed for about two minutes until it turns pale and creamy. Slowly add in the powdered sugar, cream, vanilla, and salt, then beat again until the frosting turns light and fluffy.
Split your frosting into separate bowls based on how many designs you're making. Add a small amount of gel food coloring to each bowl, stirring until you reach the shade you want for pumpkins, monsters, or spiders.
Fill your piping bags with the tinted frosting and get creative. Simple swirls make great pumpkins, blobs of white work as ghosts, and thin black lines piped in circles create spooky spiderwebs.
Finish each cupcake with candy eyes, mini chocolate chips, or sprinkles to bring the design to life. This is where kids especially love getting involved, since there's no wrong way to place a googly eye.