Make the Yellow Cupcakes

• Preheat the oven to 350ºF/177ºC and line a cupcake pan with 12-15 liners.
• Add the sifted cake flour, baking powder, baking soda, and salt into a bowl and whisk to combine. Set aside. 
• In the bowl of your stand mixer (a handheld mixer works fine too!), cream the butter for on high for two minutes until it's light and fluffy. Add vegetable oil and sugar, then continue to mix on med-high for another two minutes. Add the whole egg and egg yolk and mix until well combined. Add vanilla and sour cream and mix for one minute on high, scraping down the bowl and paddle once more. 
• With the mixer on low speed, add in the dry ingredients and mix until just combined, then continue mixing while you add the milk in a slow stream. Mix until just incorporated, then scrape down the sides and bottom of the bowl and give it a few stirs to make sure there are no lumps (without over-mixing). The batter will be thick.
• Spoon the yellow cake batter into the cupcake liners, filling each one between 1/2 and 2/3 full. Bake for 15-18 minutes, or until a toothpick inserted comes out clean. Allow the cupcakes to cool fully before frosting.

Make the Chocolate Buttercream

• In a stand mixer fitted with a paddle attachment, whip the butter on high speed until creamy and light in color, about five minutes. Scrape down the bowl and paddle and turn the mixer to low, then add the powdered sugar, cocoa powder, milk, vanilla extract, and salt. Continue mixing on low speed until fully combined and uniform, 2-3 minutes, scraping down the bowl and paddle as needed.

Assembly

• When the cupcakes are fully cooled, fit a piping bag with Wilton Tip 1M. Fill the piping bag with the chocolate buttercream and pipe a swirl onto each cupcake. Garnish with rainbow sprinkles.

Make The Graham Cracker Crust

• In a small bowl, stir together the graham cracker crumbs and granulated sugar. Add the melted butter and mix until well incorporated.

Make The Graham Cracker Cupcakes

• Preheat the oven to 350˚F and line a muffin pan or cupcake pan with liners. Press a spoonful of the Graham Cracker Crust into the bottom of each cupcake liner.
• In a medium sized bowl, add the graham cracker crumbs, sifted cake flour, baking powder, baking soda, and salt. Whisk to combine and set aside.
• In the bowl of a stand mixer with the paddle attachment, cream butter for one minute on high. Scrape down the bowl and paddle and add the sugar. Cream together on high for two minutes, scraping down the bowl and paddle once in between. Turn the mixer to low and add the egg and egg yolk until combined.
• Add vanilla and mix on medium for one minute. Turn the mixer to low and add all of the dry ingredients at once until just combined, then add the milk all at once. Scrape down the bowl and paddle once more and mix on low for about 30 seconds. Do not overmix.  
• Pour batter on top of the graham cracker crust bottomed liners to fill no more than ⅔ full. Bake for 17 minutes or until a toothpick inserted comes out clean. Cool completely before filling or frosting.

Make The Chocolate Buttercream

• In a stand mixer fitted with a paddle attachment, whip butter on medium speed until creamy and light in color, about four minutes. Scrape down the bowl and paddle and turn the mixer to low, then add powdered sugar, cocoa powder, milk, salt, and vanilla extract. Increase the speed to medium and beat for one full minute.

Make The Marshmallow Meringue

• Whisk the egg whites, sugar, and cream of tartar together in a small heatproof bowl. Set the bowl over a saucepan filled with an inch or two of simmering water, making sure the bottom of the bowl doesn’t touch the water (or else it will cook your eggs!). Whisk the mixture constantly until the sugar has dissolved, about 4 minutes.
• Once the sugar has dissolved, pour the mixture into the bowl of your stand mixer fitted with the whisk attachment. Add the vanilla and whisk the mixture on high for 6 full minutes, until stiff peaks form. You should be able to dip the whisk into the meringue and it forms a peak that maintains its shape when turned right side up and upside down.

Assembly

• Once the Graham Cracker Cupcakes are cooled, cut out the centers using a knife or inverted large piping tip. Fill the empty centers with Marshmallow Fluff. Fit a piping bag with Wilton tip 1M and fill it with Chocolate Buttercream, then pipe a swirl of chocolate buttercream on top of each cupcake. Sprinkle with graham cracker crumbs.
• To get the look pictured, fit one piping bag with Wilton Tip 1M and another with Wilton Tip 4B. Fill both piping bags with Marshmallow Meringue. Pipe a small swirl with Wilton Tip 1M on top of each cupcake, then pipe two stars next to each small meringue swirl with Wilton Tip 4B. Toast the meringue accents (carefully!) with a culinary torch.

Make The Banana Cupcakes

• Preheat the oven to 350ºF and prepare a muffin pan by lining with cupcake tins. Measure the flour by spooning into your measuring cup and leveling it, then whisk it together with the baking powder, baking soda, salt, and ground cinnamon and set aside.
• Place the bananas in the bowl of your stand mixer and mash them with a paddle attachment on medium for about 30 seconds. Set aside.
• Cream the butter on high for 1 minute. Add the white and brown sugars and cream on high for another 2 minutes. Turn the mixer to low, add the eggs one at a time and mix until combined.  Add the mashed bananas and vanilla and beat for 1 full minute, then scrape down the bowl and paddle. With the mixer still on low, add the dry ingredients until just combined, then add the buttermilk and mix until just combined. Give it a few stirs with your spatula to ensure that everything is nice and mixed up without overmixing. The batter will be thick.
• Spoon the batter into prepared cupcake tins ⅔ of the way full, then bake for 17 minutes, or until a toothpick inserted comes out clean. Cool the cupcakes in the pan for five minutes before removing and continuing to cool on a wire rack or flat surface.

Make The Vanilla Buttercream

• With a hand mixer or paddle attachment on your stand mixer, cream the butter on medium-high until it’s creamy and light (almost white) in color. About 7 minutes. 
• Add the sifted powdered sugar, one cup at a time, scraping down after each addition and making sure each cup is fully incorporated before adding the next one. Add vanilla, milk, and salt and mix on medium-low for another two minutes until fully incorporated. 
• Place the buttercream into an airtight container and chill in the refrigerator until ready to use.

Make The Chocolate Ganache

• Place chocolate chips into a heat resistant bowl (glass or metal). In a saucepan over medium-high heat, warm heavy whipping cream until it just starts to boil. I always look for small bubbles forming around the edge and a soft boil starting in the middle. When you see that it’s just starting to boil, pour it into your bowl of chocolate and let sit for 30 seconds, then whisk it together until it's uniform in consistency and there are no bits of chocolate left on your whisk.
• Cool ganache at room temperature for about 30 minutes, or until the ganache itself is room temperature. 

Assembly

• Once the Banana Cupcakes have cooled completely, add a scoop of cold Vanilla Buttercream on top of each one and shape it with a spoon until it resembles a scoop of real ice cream. Drizzle the buttercream with Chocolate Ganache (make sure it's room temperature, not hotter or colder than that), add the rainbow sprinkles, and place a maraschino cherry on top.

• Preheat the oven to 350°F. Prepare a muffin pan by lining with cupcake tins. 
• Sift the cake flour first, then measure it out by spooning and leveling it in your measuring cup. Add the cake flour, baking powder, baking soda, and salt into a bowl and whisk to combine. Set aside. 
• In the bowl of your stand mixer (a handheld mixer works fine too!), cream the butter for on high for two minutes until it’s light and fluffy. Add in sugar and continue to mix on high for another two minutes, scraping down the bowl and paddle as needed. Add the eggs one at a time, mixing thoroughly after each addition. Add vanilla and sour cream and mix for one minute on high, scraping down the bowl and paddle once more.
• With the mixer on low speed, add in the dry ingredients and mix until just combined. Add the milk slowly and mix until just incorporated. Scrape down the sides and bottom of the bowl and give it a few stirs to make sure there are no lumps (without over-mixing). The batter will be slightly thick.
• Spoon batter into the cupcake tins until they’re about ⅔ full, then bake for 17 minutes. They’re done when they spring back to the touch and a toothpick inserted into the middle comes out clean. Let the cupcakes cool in the pan for five minutes before removing them from the pan and continuing to cool them for at least an hour. Make sure they’re entirely room temperature before applying any frosting.