See recipe Note before starting, because if you only plan to use 1 or 2 of these designs, you can scale down the buttercream recipe. With a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium speed until creamy, about 2 minutes. Add 5 and 1/2 cups (660g) confectioners’ sugar, the heavy cream, and vanilla extract. Beat on low speed for 30 seconds, then increase to medium-high speed and beat for 2 full minutes. Taste. Add a pinch of salt if frosting is too sweet. I always add 1/8 teaspoon. If you notice a lot of air bubbles in your buttercream, stir by hand with a silicone spatula or wooden spoon to “mash” the frosting up against the side of the bowl, which helps pops the bubbles. Do this until most of the air bubbles pop, about 1–2 minutes. This trick requires a lot of arm muscle!

You can control the consistency of the frosting at this point—add up to 1/2 cup (60g) more confectioners’ sugar if frosting is too thin or more heavy cream if frosting is too thick (add only 1 Tablespoon (15ml) at a time, beat together, then taste and add more if desired).

Divide the frosting into bowls for however many colors you’re making. If you’re making all 4 designs, divide the frosting into 5 bowls—you’ll need less black frosting than other colors. Tint each bowl with a few drops of gel food coloring, stirring well, until you reach your desired shade of color. Keep 1 bowl white for the spider cupcakes. Note that I used 2 colors of gel food coloring (Fuchsia + Violet) to make a pinkish purple for the purple monster cupcakes. If you’d like to tone down the brightness of any color, use a toothpick to add a tiny dot of black gel food coloring to the bowl, then stir well. Remember that the color will continue to darken as the frosting sits.

Continue with the instructions below for each design.

Fit a piping bag with a small open star piping tip (I use Wilton #21), and a coupler, if using. Fill the piping bag with green frosting. Starting from the outside and working your way in to the center, pipe a spiral onto the cupcake. Place a large candy eyeball in the center, tapping it down gently so it sticks to the frosting.

Fit a piping bag with a small open star piping tip (I use Wilton #21), and a coupler, if using. Fill the piping bag with purple frosting. Using steady, medium pressure, begin piping stars all over the surface of the cupcake until it’s covered. Gently press small candy eyeballs into the frosting, and finish with sprinkles, if desired.

Fit a piping bag with a large petal tip (I use Wilton #125), and then fill with orange frosting. Fit a piping bag with a small open star tip (I use Wilton #21), and then fill with green frosting. Finally, fit a piping bag with a small round tip (I use Wilton #4), and then fill with black frosting. Start by piping on the orange frosting. Starting on one side, pipe a rounded line from top to bottom, following the curve of the cupcake. Repeat on the other side, then work your way in towards the center, alternating sides, finishing with a vertical line down the center. Use the green frosting to pipe on the pumpkin stem. Use the black frosting to pipe on the eyes, nose, and mouth. Make it as goofy or spooky as you like!

You only need white and black frosting for this design. Fit a piping bag with a small round tip (I use Wilton #4). Fill the piping bag with black frosting. With a small offset icing spatula or a knife, spread the white frosting onto the cupcake, smoothing around the outside and across the top. To make the web, use the black frosting to pipe 3 criss-crossing straight lines across the top, so you have 6 triangle-shaped sections. Connect them with slightly curved lines, 2 between each section, to make a web. To make the spider, place half of a mini Oreo cookie onto the web, gently pressing it into the frosting so it sticks. Pipe 2 tiny dots of black frosting for the eyes, then stick 2 tiny candy eyeballs to the black frosting dots. Finish by piping 4 black lines on either side of the Oreo, to make 8 little spider legs.

Store at room temperature, uncovered, for up to a few hours before serving. See make ahead instructions below for more details. Cover and store leftover cupcakes in the refrigerator for up to 5 days. I recommend a cupcake carrier for storing and transporting decorated cupcakes.