Spray the wells of a 12-cup standard cupcake pan with nonstick cooking spray.: The kitchen will smell faintly of oil as you coat the pan, and a light, even spray keeps the finished cupcakes unmolding cleanly without tearing. I always tap out excess spray on a paper towel to avoid pooling. A common mistake is spraying too late, then the hot mixture can stick; prepare the pan before you melt anything so you can work immediately.
In large pan, melt butter over low heat. Add the marshmallows to the pan and stir until completely melted.: You will notice the butter shimmer as it warms, then the marshmallows soften and collapse into a glossy, velvety pool, releasing a warm pumpkin spice aroma. Stir slowly with a heatproof spatula to keep the mixture smooth and prevent burning. Keep the flame low, because higher heat can make marshmallows grainy or scorched, which makes the base lose its silky texture.
Gradually add crispy rice cereal; stirring until well coated.: As you fold in the crispy rice cereal , you will hear a satisfying rustle as each flake becomes glazed in the spiced marshmallow. Add the cereal in batches to ensure each portion is evenly coated, which preserves the light, crunchy texture. The mistake to avoid here is dumping it all at once, which creates uneven clumps and makes it hard to press into the pan uniformly.
Use a buttered spatula or clean, buttered hands to firmly press the mixture into the wells of the prepared pan. You’ll need to work quickly, so the mixture doesn’t set up in the pan.: When pressing the mixture in, you should feel a tacky warmth under your palms and see the surface become smooth and shiny as air pockets compress. Press firmly to ensure cohesive cups that hold together, but do not over compress or you will lose the airy crunch. Working too slowly lets the mixture set and become brittle, making it hard to shape and resulting in crumbly edges.
Cool for about 15 minutes. Remove marshmallow treat cupcakes from the pan and prepare the frosting.: The cupcakes will steam faintly as they cool, and the edges will firm up to a springy texture that gives slightly under gentle pressure. Letting them cool fully prevents the frosting from sliding off, so resist the urge to frost warm cups. A common error is frosting them too soon, which melts the frosting and ruins the presentation.
In a the bowl of a stand mixer fitted with the paddle attachment, cream together, cream cheese, and butter until well combined about 5 minutes.: As you cream, the bowl will reveal a silky, pale mixture with a faint tang from the cream cheese . Stop and scrape the sides periodically to ensure even blending. If the cream cheese is not at room temperature, you will end up with lumps, so plan ahead to let it soften fully for a smooth frosting base.
With the mixer on low, gradually add the confectioners’ sugar until thoroughly incorporated and smooth. Add vanilla and mix to combine. Turn mixer to medium speed and mix for approximately 5 more minutes.: The powdered sugar will dust the bowl initially, then dissolve into a thick, snow like cream that becomes glossy as you whip. Adding the vanilla at the right moment helps it bloom into the mixture, lifting the aroma. Over mixing once the sugar is added can introduce too much air and make the frosting look pale and airy, so mix until smooth and pipeable rather than fluffier than needed.
Pipe frosting onto marshmallow treat cupcakes. If desired, top with additional Campfire® Pumpkin Spice Marshmallow.: When piping, you will feel the bag fill and the frosting glide out smoothly if it is at the right consistency, creating clean peaks and swirls that hold shape. A small dab of frosting on the center helps secure any marshmallow topper. The biggest mistake here is using frosting that is too soft, which will flatten; chill briefly if it becomes too loose, then continue piping for crisp definition.